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+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/* This tool is based on a paper from SIGGRAPH '95:
+ * "Intelligent Scissors for Image Composition", Eric N. Mortensen and
+ * William A. Barrett, Brigham Young University.
+ *
+ * thanks to Professor D. Forsyth for prompting us to implement this tool. */
+
+/* Personal note: Dr. Barrett, one of the authors of the paper written above
+ * is not only one of the most brilliant people I have ever met, he is an
+ * incredible professor who genuinely cares about his students and wants them
+ * to learn as much as they can about the topic.
+ *
+ * I didn't even notice I was taking a class from the person who wrote the
+ * paper until halfway through the semester.
+ * -- Rockwalrus
+ */
+
+/* The history of this implementation is lonog and varied. It was
+ * originally done by Spencer and Peter, and worked fine in the 0.54
+ * (motif only) release of GIMP. Later revisions (0.99.something
+ * until about 1.1.4) completely changed the algorithm used, until it
+ * bore little resemblance to the one described in the paper above.
+ * The 0.54 version of the algorithm was then forwards ported to 1.1.4
+ * by Austin Donnelly.
+ */
+
+/* Livewire boundary implementation done by Laramie Leavitt */
+
+#include "config.h"
+
+#include <stdlib.h>
+
+#include <gegl.h>
+#include <gtk/gtk.h>
+#include <gdk/gdkkeysyms.h>
+
+#include "libgimpmath/gimpmath.h"
+#include "libgimpwidgets/gimpwidgets.h"
+
+#include "tools-types.h"
+
+#include "gegl/gimp-gegl-utils.h"
+
+#include "core/gimpchannel.h"
+#include "core/gimpchannel-select.h"
+#include "core/gimpimage.h"
+#include "core/gimppickable.h"
+#include "core/gimpscanconvert.h"
+#include "core/gimptempbuf.h"
+#include "core/gimptoolinfo.h"
+
+#include "widgets/gimphelp-ids.h"
+#include "widgets/gimpwidgets-utils.h"
+
+#include "display/gimpcanvasitem.h"
+#include "display/gimpdisplay.h"
+
+#include "gimpiscissorsoptions.h"
+#include "gimpiscissorstool.h"
+#include "gimptilehandleriscissors.h"
+#include "gimptoolcontrol.h"
+
+#include "gimp-intl.h"
+
+
+/* defines */
+#define GRADIENT_SEARCH 32 /* how far to look when snapping to an edge */
+#define EXTEND_BY 0.2 /* proportion to expand cost map by */
+#define FIXED 5 /* additional fixed size to expand cost map */
+
+#define COST_WIDTH 2 /* number of bytes for each pixel in cost map */
+
+/* weight to give between gradient (_G) and direction (_D) */
+#define OMEGA_D 0.2
+#define OMEGA_G 0.8
+
+/* sentinel to mark seed point in ?cost? map */
+#define SEED_POINT 9
+
+/* Functional defines */
+#define PIXEL_COST(x) ((x) >> 8)
+#define PIXEL_DIR(x) ((x) & 0x000000ff)
+
+
+struct _ISegment
+{
+ gint x1, y1;
+ gint x2, y2;
+ GPtrArray *points;
+};
+
+struct _ICurve
+{
+ GQueue *segments;
+ gboolean first_point;
+ gboolean closed;
+};
+
+
+/* local function prototypes */
+
+static void gimp_iscissors_tool_finalize (GObject *object);
+
+static void gimp_iscissors_tool_control (GimpTool *tool,
+ GimpToolAction action,
+ GimpDisplay *display);
+static void gimp_iscissors_tool_button_press (GimpTool *tool,
+ const GimpCoords *coords,
+ guint32 time,
+ GdkModifierType state,
+ GimpButtonPressType press_type,
+ GimpDisplay *display);
+static void gimp_iscissors_tool_button_release (GimpTool *tool,
+ const GimpCoords *coords,
+ guint32 time,
+ GdkModifierType state,
+ GimpButtonReleaseType release_type,
+ GimpDisplay *display);
+static void gimp_iscissors_tool_motion (GimpTool *tool,
+ const GimpCoords *coords,
+ guint32 time,
+ GdkModifierType state,
+ GimpDisplay *display);
+static void gimp_iscissors_tool_oper_update (GimpTool *tool,
+ const GimpCoords *coords,
+ GdkModifierType state,
+ gboolean proximity,
+ GimpDisplay *display);
+static void gimp_iscissors_tool_cursor_update (GimpTool *tool,
+ const GimpCoords *coords,
+ GdkModifierType state,
+ GimpDisplay *display);
+static gboolean gimp_iscissors_tool_key_press (GimpTool *tool,
+ GdkEventKey *kevent,
+ GimpDisplay *display);
+static const gchar * gimp_iscissors_tool_can_undo (GimpTool *tool,
+ GimpDisplay *display);
+static const gchar * gimp_iscissors_tool_can_redo (GimpTool *tool,
+ GimpDisplay *display);
+static gboolean gimp_iscissors_tool_undo (GimpTool *tool,
+ GimpDisplay *display);
+static gboolean gimp_iscissors_tool_redo (GimpTool *tool,
+ GimpDisplay *display);
+
+static void gimp_iscissors_tool_draw (GimpDrawTool *draw_tool);
+
+static void gimp_iscissors_tool_push_undo (GimpIscissorsTool *iscissors);
+static void gimp_iscissors_tool_pop_undo (GimpIscissorsTool *iscissors);
+static void gimp_iscissors_tool_free_redo (GimpIscissorsTool *iscissors);
+
+static void gimp_iscissors_tool_halt (GimpIscissorsTool *iscissors,
+ GimpDisplay *display);
+static void gimp_iscissors_tool_commit (GimpIscissorsTool *iscissors,
+ GimpDisplay *display);
+
+static void iscissors_convert (GimpIscissorsTool *iscissors,
+ GimpDisplay *display);
+static GeglBuffer * gradient_map_new (GimpPickable *pickable);
+
+static void find_optimal_path (GeglBuffer *gradient_map,
+ GimpTempBuf *dp_buf,
+ gint x1,
+ gint y1,
+ gint x2,
+ gint y2,
+ gint xs,
+ gint ys);
+static void find_max_gradient (GimpIscissorsTool *iscissors,
+ GimpPickable *pickable,
+ gint *x,
+ gint *y);
+static void calculate_segment (GimpIscissorsTool *iscissors,
+ ISegment *segment);
+static GimpCanvasItem * iscissors_draw_segment (GimpDrawTool *draw_tool,
+ ISegment *segment);
+
+static gint mouse_over_vertex (GimpIscissorsTool *iscissors,
+ gdouble x,
+ gdouble y);
+static gboolean clicked_on_vertex (GimpIscissorsTool *iscissors,
+ gdouble x,
+ gdouble y);
+static GList * mouse_over_segment (GimpIscissorsTool *iscissors,
+ gdouble x,
+ gdouble y);
+static gboolean clicked_on_segment (GimpIscissorsTool *iscissors,
+ gdouble x,
+ gdouble y);
+
+static GPtrArray * plot_pixels (GimpTempBuf *dp_buf,
+ gint x1,
+ gint y1,
+ gint xs,
+ gint ys,
+ gint xe,
+ gint ye);
+
+static ISegment * isegment_new (gint x1,
+ gint y1,
+ gint x2,
+ gint y2);
+static ISegment * isegment_copy (ISegment *segment);
+static void isegment_free (ISegment *segment);
+
+static ICurve * icurve_new (void);
+static ICurve * icurve_copy (ICurve *curve);
+static void icurve_clear (ICurve *curve);
+static void icurve_free (ICurve *curve);
+
+static ISegment * icurve_append_segment (ICurve *curve,
+ gint x1,
+ gint y1,
+ gint x2,
+ gint y2);
+static ISegment * icurve_insert_segment (ICurve *curve,
+ GList *sibling,
+ gint x1,
+ gint y1,
+ gint x2,
+ gint y2);
+static void icurve_delete_segment (ICurve *curve,
+ ISegment *segment);
+
+static void icurve_close (ICurve *curve);
+
+static GimpScanConvert *
+ icurve_create_scan_convert (ICurve *curve);
+
+
+/* static variables */
+
+/* where to move on a given link direction */
+static const gint move[8][2] =
+{
+ { 1, 0 },
+ { 0, 1 },
+ { -1, 1 },
+ { 1, 1 },
+ { -1, 0 },
+ { 0, -1 },
+ { 1, -1 },
+ { -1, -1 },
+};
+
+/* IE:
+ * '---+---+---`
+ * | 7 | 5 | 6 |
+ * +---+---+---+
+ * | 4 | | 0 |
+ * +---+---+---+
+ * | 2 | 1 | 3 |
+ * `---+---+---'
+ */
+
+static gfloat distance_weights[GRADIENT_SEARCH * GRADIENT_SEARCH];
+
+static gint diagonal_weight[256];
+static gint direction_value[256][4];
+
+
+G_DEFINE_TYPE (GimpIscissorsTool, gimp_iscissors_tool,
+ GIMP_TYPE_SELECTION_TOOL)
+
+#define parent_class gimp_iscissors_tool_parent_class
+
+
+void
+gimp_iscissors_tool_register (GimpToolRegisterCallback callback,
+ gpointer data)
+{
+ (* callback) (GIMP_TYPE_ISCISSORS_TOOL,
+ GIMP_TYPE_ISCISSORS_OPTIONS,
+ gimp_iscissors_options_gui,
+ 0,
+ "gimp-iscissors-tool",
+ _("Scissors Select"),
+ _("Scissors Select Tool: Select shapes using intelligent edge-fitting"),
+ N_("Intelligent _Scissors"),
+ "I",
+ NULL, GIMP_HELP_TOOL_ISCISSORS,
+ GIMP_ICON_TOOL_ISCISSORS,
+ data);
+}
+
+static void
+gimp_iscissors_tool_class_init (GimpIscissorsToolClass *klass)
+{
+ GObjectClass *object_class = G_OBJECT_CLASS (klass);
+ GimpToolClass *tool_class = GIMP_TOOL_CLASS (klass);
+ GimpDrawToolClass *draw_tool_class = GIMP_DRAW_TOOL_CLASS (klass);
+ gint i, j;
+ gint radius;
+
+ object_class->finalize = gimp_iscissors_tool_finalize;
+
+ tool_class->control = gimp_iscissors_tool_control;
+ tool_class->button_press = gimp_iscissors_tool_button_press;
+ tool_class->button_release = gimp_iscissors_tool_button_release;
+ tool_class->motion = gimp_iscissors_tool_motion;
+ tool_class->key_press = gimp_iscissors_tool_key_press;
+ tool_class->oper_update = gimp_iscissors_tool_oper_update;
+ tool_class->cursor_update = gimp_iscissors_tool_cursor_update;
+ tool_class->can_undo = gimp_iscissors_tool_can_undo;
+ tool_class->can_redo = gimp_iscissors_tool_can_redo;
+ tool_class->undo = gimp_iscissors_tool_undo;
+ tool_class->redo = gimp_iscissors_tool_redo;
+
+ draw_tool_class->draw = gimp_iscissors_tool_draw;
+
+ for (i = 0; i < 256; i++)
+ {
+ /* The diagonal weight array */
+ diagonal_weight[i] = (int) (i * G_SQRT2);
+
+ /* The direction value array */
+ direction_value[i][0] = (127 - abs (127 - i)) * 2;
+ direction_value[i][1] = abs (127 - i) * 2;
+ direction_value[i][2] = abs (191 - i) * 2;
+ direction_value[i][3] = abs (63 - i) * 2;
+ }
+
+ /* set the 256th index of the direction_values to the highest cost */
+ direction_value[255][0] = 255;
+ direction_value[255][1] = 255;
+ direction_value[255][2] = 255;
+ direction_value[255][3] = 255;
+
+ /* compute the distance weights */
+ radius = GRADIENT_SEARCH >> 1;
+
+ for (i = 0; i < GRADIENT_SEARCH; i++)
+ for (j = 0; j < GRADIENT_SEARCH; j++)
+ distance_weights[i * GRADIENT_SEARCH + j] =
+ 1.0 / (1 + sqrt (SQR (i - radius) + SQR (j - radius)));
+}
+
+static void
+gimp_iscissors_tool_init (GimpIscissorsTool *iscissors)
+{
+ GimpTool *tool = GIMP_TOOL (iscissors);
+
+ gimp_tool_control_set_scroll_lock (tool->control, TRUE);
+ gimp_tool_control_set_snap_to (tool->control, FALSE);
+ gimp_tool_control_set_preserve (tool->control, FALSE);
+ gimp_tool_control_set_dirty_mask (tool->control,
+ GIMP_DIRTY_IMAGE_SIZE |
+ GIMP_DIRTY_ACTIVE_DRAWABLE);
+ gimp_tool_control_set_tool_cursor (tool->control,
+ GIMP_TOOL_CURSOR_ISCISSORS);
+
+ iscissors->op = ISCISSORS_OP_NONE;
+ iscissors->curve = icurve_new ();
+ iscissors->state = NO_ACTION;
+}
+
+static void
+gimp_iscissors_tool_finalize (GObject *object)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (object);
+
+ icurve_free (iscissors->curve);
+ iscissors->curve = NULL;
+
+ G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gimp_iscissors_tool_control (GimpTool *tool,
+ GimpToolAction action,
+ GimpDisplay *display)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (tool);
+
+ switch (action)
+ {
+ case GIMP_TOOL_ACTION_PAUSE:
+ case GIMP_TOOL_ACTION_RESUME:
+ break;
+
+ case GIMP_TOOL_ACTION_HALT:
+ gimp_iscissors_tool_halt (iscissors, display);
+ break;
+
+ case GIMP_TOOL_ACTION_COMMIT:
+ gimp_iscissors_tool_commit (iscissors, display);
+ break;
+ }
+
+ GIMP_TOOL_CLASS (parent_class)->control (tool, action, display);
+}
+
+static void
+gimp_iscissors_tool_button_press (GimpTool *tool,
+ const GimpCoords *coords,
+ guint32 time,
+ GdkModifierType state,
+ GimpButtonPressType press_type,
+ GimpDisplay *display)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (tool);
+ GimpIscissorsOptions *options = GIMP_ISCISSORS_TOOL_GET_OPTIONS (tool);
+ GimpImage *image = gimp_display_get_image (display);
+ ISegment *segment;
+
+ iscissors->x = RINT (coords->x);
+ iscissors->y = RINT (coords->y);
+
+ /* If the tool was being used in another image...reset it */
+ if (display != tool->display)
+ gimp_tool_control (tool, GIMP_TOOL_ACTION_HALT, display);
+
+ gimp_tool_control_activate (tool->control);
+ tool->display = display;
+
+ gimp_draw_tool_pause (GIMP_DRAW_TOOL (tool));
+
+ switch (iscissors->state)
+ {
+ case NO_ACTION:
+ iscissors->state = SEED_PLACEMENT;
+
+ if (! (state & gimp_get_extend_selection_mask ()))
+ find_max_gradient (iscissors, GIMP_PICKABLE (image),
+ &iscissors->x, &iscissors->y);
+
+ iscissors->x = CLAMP (iscissors->x, 0, gimp_image_get_width (image) - 1);
+ iscissors->y = CLAMP (iscissors->y, 0, gimp_image_get_height (image) - 1);
+
+ gimp_iscissors_tool_push_undo (iscissors);
+
+ segment = icurve_append_segment (iscissors->curve,
+ iscissors->x,
+ iscissors->y,
+ iscissors->x,
+ iscissors->y);
+
+ /* Initialize the draw tool only on starting the tool */
+ gimp_draw_tool_start (GIMP_DRAW_TOOL (tool), display);
+ break;
+
+ default:
+ /* Check if the mouse click occurred on a vertex or the curve itself */
+ if (clicked_on_vertex (iscissors, coords->x, coords->y))
+ {
+ iscissors->state = SEED_ADJUSTMENT;
+
+ /* recalculate both segments */
+ if (iscissors->segment1)
+ {
+ iscissors->segment1->x1 = iscissors->x;
+ iscissors->segment1->y1 = iscissors->y;
+
+ if (options->interactive)
+ calculate_segment (iscissors, iscissors->segment1);
+ }
+
+ if (iscissors->segment2)
+ {
+ iscissors->segment2->x2 = iscissors->x;
+ iscissors->segment2->y2 = iscissors->y;
+
+ if (options->interactive)
+ calculate_segment (iscissors, iscissors->segment2);
+ }
+ }
+ /* If the iscissors is closed, check if the click was inside */
+ else if (iscissors->curve->closed && iscissors->mask &&
+ gimp_pickable_get_opacity_at (GIMP_PICKABLE (iscissors->mask),
+ iscissors->x,
+ iscissors->y))
+ {
+ gimp_tool_control (tool, GIMP_TOOL_ACTION_COMMIT, display);
+ }
+ else if (! iscissors->curve->closed)
+ {
+ /* if we're not closed, we're adding a new point */
+
+ ISegment *last = g_queue_peek_tail (iscissors->curve->segments);
+
+ iscissors->state = SEED_PLACEMENT;
+
+ gimp_iscissors_tool_push_undo (iscissors);
+
+ if (last->x1 == last->x2 &&
+ last->y1 == last->y2)
+ {
+ last->x2 = iscissors->x;
+ last->y2 = iscissors->y;
+
+ if (options->interactive)
+ calculate_segment (iscissors, last);
+ }
+ else
+ {
+ segment = icurve_append_segment (iscissors->curve,
+ last->x2,
+ last->y2,
+ iscissors->x,
+ iscissors->y);
+
+ if (options->interactive)
+ calculate_segment (iscissors, segment);
+ }
+ }
+ break;
+ }
+
+ gimp_draw_tool_resume (GIMP_DRAW_TOOL (tool));
+}
+
+static void
+iscissors_convert (GimpIscissorsTool *iscissors,
+ GimpDisplay *display)
+{
+ GimpSelectionOptions *options = GIMP_SELECTION_TOOL_GET_OPTIONS (iscissors);
+ GimpImage *image = gimp_display_get_image (display);
+ GimpScanConvert *sc;
+
+ sc = icurve_create_scan_convert (iscissors->curve);
+
+ if (iscissors->mask)
+ g_object_unref (iscissors->mask);
+
+ iscissors->mask = gimp_channel_new_mask (image,
+ gimp_image_get_width (image),
+ gimp_image_get_height (image));
+ gimp_scan_convert_render (sc,
+ gimp_drawable_get_buffer (GIMP_DRAWABLE (iscissors->mask)),
+ 0, 0, options->antialias);
+
+ gimp_scan_convert_free (sc);
+}
+
+static void
+gimp_iscissors_tool_button_release (GimpTool *tool,
+ const GimpCoords *coords,
+ guint32 time,
+ GdkModifierType state,
+ GimpButtonReleaseType release_type,
+ GimpDisplay *display)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (tool);
+ GimpIscissorsOptions *options = GIMP_ISCISSORS_TOOL_GET_OPTIONS (tool);
+
+ gimp_tool_control_halt (tool->control);
+
+ /* Make sure X didn't skip the button release event -- as it's known
+ * to do
+ */
+ if (iscissors->state == WAITING)
+ return;
+
+ gimp_draw_tool_pause (GIMP_DRAW_TOOL (tool));
+
+ if (release_type != GIMP_BUTTON_RELEASE_CANCEL)
+ {
+ /* Progress to the next stage of intelligent selection */
+ switch (iscissors->state)
+ {
+ case SEED_PLACEMENT:
+ /* Add a new segment */
+ if (! iscissors->curve->first_point)
+ {
+ /* Determine if we're connecting to the first point */
+
+ ISegment *segment = g_queue_peek_head (iscissors->curve->segments);
+
+ if (gimp_draw_tool_on_handle (GIMP_DRAW_TOOL (tool), display,
+ iscissors->x, iscissors->y,
+ GIMP_HANDLE_CIRCLE,
+ segment->x1, segment->y1,
+ GIMP_TOOL_HANDLE_SIZE_CIRCLE,
+ GIMP_TOOL_HANDLE_SIZE_CIRCLE,
+ GIMP_HANDLE_ANCHOR_CENTER))
+ {
+ iscissors->x = segment->x1;
+ iscissors->y = segment->y1;
+
+ icurve_close (iscissors->curve);
+
+ if (! options->interactive)
+ {
+ segment = g_queue_peek_tail (iscissors->curve->segments);
+ calculate_segment (iscissors, segment);
+ }
+
+ gimp_iscissors_tool_free_redo (iscissors);
+ }
+ else
+ {
+ segment = g_queue_peek_tail (iscissors->curve->segments);
+
+ if (segment->x1 != segment->x2 ||
+ segment->y1 != segment->y2)
+ {
+ if (! options->interactive)
+ calculate_segment (iscissors, segment);
+
+ gimp_iscissors_tool_free_redo (iscissors);
+ }
+ else
+ {
+ gimp_iscissors_tool_pop_undo (iscissors);
+ }
+ }
+ }
+ else /* this was our first point */
+ {
+ iscissors->curve->first_point = FALSE;
+
+ gimp_iscissors_tool_free_redo (iscissors);
+ }
+ break;
+
+ case SEED_ADJUSTMENT:
+ if (state & gimp_get_modify_selection_mask ())
+ {
+ if (iscissors->segment1 && iscissors->segment2)
+ {
+ icurve_delete_segment (iscissors->curve,
+ iscissors->segment2);
+
+ calculate_segment (iscissors, iscissors->segment1);
+ }
+ }
+ else
+ {
+ /* recalculate both segments */
+
+ if (iscissors->segment1)
+ {
+ if (! options->interactive)
+ calculate_segment (iscissors, iscissors->segment1);
+ }
+
+ if (iscissors->segment2)
+ {
+ if (! options->interactive)
+ calculate_segment (iscissors, iscissors->segment2);
+ }
+ }
+
+ gimp_iscissors_tool_free_redo (iscissors);
+ break;
+
+ default:
+ break;
+ }
+ }
+ else
+ {
+ switch (iscissors->state)
+ {
+ case SEED_PLACEMENT:
+ case SEED_ADJUSTMENT:
+ gimp_iscissors_tool_pop_undo (iscissors);
+ break;
+
+ default:
+ break;
+ }
+ }
+
+ if (iscissors->curve->first_point)
+ iscissors->state = NO_ACTION;
+ else
+ iscissors->state = WAITING;
+
+ gimp_draw_tool_resume (GIMP_DRAW_TOOL (tool));
+
+ /* convert the curves into a region */
+ if (iscissors->curve->closed)
+ iscissors_convert (iscissors, display);
+}
+
+static void
+gimp_iscissors_tool_motion (GimpTool *tool,
+ const GimpCoords *coords,
+ guint32 time,
+ GdkModifierType state,
+ GimpDisplay *display)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (tool);
+ GimpIscissorsOptions *options = GIMP_ISCISSORS_TOOL_GET_OPTIONS (tool);
+ GimpImage *image = gimp_display_get_image (display);
+ ISegment *segment;
+
+ if (iscissors->state == NO_ACTION)
+ return;
+
+ gimp_draw_tool_pause (GIMP_DRAW_TOOL (tool));
+
+ iscissors->x = RINT (coords->x);
+ iscissors->y = RINT (coords->y);
+
+ /* Hold the shift key down to disable the auto-edge snap feature */
+ if (! (state & gimp_get_extend_selection_mask ()))
+ find_max_gradient (iscissors, GIMP_PICKABLE (image),
+ &iscissors->x, &iscissors->y);
+
+ iscissors->x = CLAMP (iscissors->x, 0, gimp_image_get_width (image) - 1);
+ iscissors->y = CLAMP (iscissors->y, 0, gimp_image_get_height (image) - 1);
+
+ switch (iscissors->state)
+ {
+ case SEED_PLACEMENT:
+ segment = g_queue_peek_tail (iscissors->curve->segments);
+
+ segment->x2 = iscissors->x;
+ segment->y2 = iscissors->y;
+
+ if (iscissors->curve->first_point)
+ {
+ segment->x1 = segment->x2;
+ segment->y1 = segment->y2;
+ }
+ else
+ {
+ if (options->interactive)
+ calculate_segment (iscissors, segment);
+ }
+ break;
+
+ case SEED_ADJUSTMENT:
+ if (iscissors->segment1)
+ {
+ iscissors->segment1->x1 = iscissors->x;
+ iscissors->segment1->y1 = iscissors->y;
+
+ if (options->interactive)
+ calculate_segment (iscissors, iscissors->segment1);
+ }
+
+ if (iscissors->segment2)
+ {
+ iscissors->segment2->x2 = iscissors->x;
+ iscissors->segment2->y2 = iscissors->y;
+
+ if (options->interactive)
+ calculate_segment (iscissors, iscissors->segment2);
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ gimp_draw_tool_resume (GIMP_DRAW_TOOL (tool));
+}
+
+static void
+gimp_iscissors_tool_draw (GimpDrawTool *draw_tool)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (draw_tool);
+ GimpIscissorsOptions *options = GIMP_ISCISSORS_TOOL_GET_OPTIONS (draw_tool);
+ GimpCanvasItem *item;
+ GList *list;
+
+ /* First, render all segments and lines */
+ if (! iscissors->curve->first_point)
+ {
+ for (list = g_queue_peek_head_link (iscissors->curve->segments);
+ list;
+ list = g_list_next (list))
+ {
+ ISegment *segment = list->data;
+
+ /* plot the segment */
+ item = iscissors_draw_segment (draw_tool, segment);
+
+ /* if this segment is currently being added or adjusted */
+ if ((iscissors->state == SEED_PLACEMENT &&
+ ! list->next)
+ ||
+ (iscissors->state == SEED_ADJUSTMENT &&
+ (segment == iscissors->segment1 ||
+ segment == iscissors->segment2)))
+ {
+ if (! options->interactive)
+ item = gimp_draw_tool_add_line (draw_tool,
+ segment->x1, segment->y1,
+ segment->x2, segment->y2);
+
+ if (item)
+ gimp_canvas_item_set_highlight (item, TRUE);
+ }
+ }
+ }
+
+ /* Then, render the handles on top of the segments */
+ for (list = g_queue_peek_head_link (iscissors->curve->segments);
+ list;
+ list = g_list_next (list))
+ {
+ ISegment *segment = list->data;
+
+ if (! iscissors->curve->first_point)
+ {
+ gboolean adjustment = (iscissors->state == SEED_ADJUSTMENT &&
+ segment == iscissors->segment1);
+
+ item = gimp_draw_tool_add_handle (draw_tool,
+ adjustment ?
+ GIMP_HANDLE_CROSS :
+ GIMP_HANDLE_FILLED_CIRCLE,
+ segment->x1,
+ segment->y1,
+ GIMP_TOOL_HANDLE_SIZE_CIRCLE,
+ GIMP_TOOL_HANDLE_SIZE_CIRCLE,
+ GIMP_HANDLE_ANCHOR_CENTER);
+
+ if (adjustment)
+ gimp_canvas_item_set_highlight (item, TRUE);
+ }
+
+ /* Draw the last point if the curve is not closed */
+ if (! list->next && ! iscissors->curve->closed)
+ {
+ gboolean placement = (iscissors->state == SEED_PLACEMENT);
+
+ item = gimp_draw_tool_add_handle (draw_tool,
+ placement ?
+ GIMP_HANDLE_CROSS :
+ GIMP_HANDLE_FILLED_CIRCLE,
+ segment->x2,
+ segment->y2,
+ GIMP_TOOL_HANDLE_SIZE_CIRCLE,
+ GIMP_TOOL_HANDLE_SIZE_CIRCLE,
+ GIMP_HANDLE_ANCHOR_CENTER);
+
+ if (placement)
+ gimp_canvas_item_set_highlight (item, TRUE);
+ }
+ }
+}
+
+static GimpCanvasItem *
+iscissors_draw_segment (GimpDrawTool *draw_tool,
+ ISegment *segment)
+{
+ GimpCanvasItem *item;
+ GimpVector2 *points;
+ gpointer *point;
+ gint i, len;
+
+ if (! segment->points)
+ return NULL;
+
+ len = segment->points->len;
+
+ points = g_new (GimpVector2, len);
+
+ for (i = 0, point = segment->points->pdata; i < len; i++, point++)
+ {
+ guint32 coords = GPOINTER_TO_INT (*point);
+
+ points[i].x = (coords & 0x0000ffff);
+ points[i].y = (coords >> 16);
+ }
+
+ item = gimp_draw_tool_add_lines (draw_tool, points, len, NULL, FALSE);
+
+ g_free (points);
+
+ return item;
+}
+
+static void
+gimp_iscissors_tool_oper_update (GimpTool *tool,
+ const GimpCoords *coords,
+ GdkModifierType state,
+ gboolean proximity,
+ GimpDisplay *display)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (tool);
+
+ GIMP_TOOL_CLASS (parent_class)->oper_update (tool, coords, state, proximity,
+ display);
+ /* parent sets a message in the status bar, but it will be replaced here */
+
+ if (mouse_over_vertex (iscissors, coords->x, coords->y) > 1)
+ {
+ GdkModifierType snap_mask = gimp_get_extend_selection_mask ();
+ GdkModifierType remove_mask = gimp_get_modify_selection_mask ();
+
+ if (state & remove_mask)
+ {
+ gimp_tool_replace_status (tool, display,
+ _("Click to remove this point"));
+ iscissors->op = ISCISSORS_OP_REMOVE_POINT;
+ }
+ else
+ {
+ gchar *status =
+ gimp_suggest_modifiers (_("Click-Drag to move this point"),
+ (snap_mask | remove_mask) & ~state,
+ _("%s: disable auto-snap"),
+ _("%s: remove this point"),
+ NULL);
+ gimp_tool_replace_status (tool, display, "%s", status);
+ g_free (status);
+ iscissors->op = ISCISSORS_OP_MOVE_POINT;
+ }
+ }
+ else if (mouse_over_segment (iscissors, coords->x, coords->y))
+ {
+ ISegment *segment = g_queue_peek_head (iscissors->curve->segments);
+
+ if (gimp_draw_tool_on_handle (GIMP_DRAW_TOOL (tool), display,
+ RINT (coords->x), RINT (coords->y),
+ GIMP_HANDLE_CIRCLE,
+ segment->x1, segment->y1,
+ GIMP_TOOL_HANDLE_SIZE_CIRCLE,
+ GIMP_TOOL_HANDLE_SIZE_CIRCLE,
+ GIMP_HANDLE_ANCHOR_CENTER))
+ {
+ gimp_tool_replace_status (tool, display,
+ _("Click to close the curve"));
+ iscissors->op = ISCISSORS_OP_CONNECT;
+ }
+ else
+ {
+ gimp_tool_replace_status (tool, display,
+ _("Click to add a point on this segment"));
+ iscissors->op = ISCISSORS_OP_ADD_POINT;
+ }
+ }
+ else if (iscissors->curve->closed && iscissors->mask)
+ {
+ if (gimp_pickable_get_opacity_at (GIMP_PICKABLE (iscissors->mask),
+ RINT (coords->x),
+ RINT (coords->y)))
+ {
+ if (proximity)
+ {
+ gimp_tool_replace_status (tool, display,
+ _("Click or press Enter to convert to"
+ " a selection"));
+ }
+ iscissors->op = ISCISSORS_OP_SELECT;
+ }
+ else
+ {
+ if (proximity)
+ {
+ gimp_tool_replace_status (tool, display,
+ _("Press Enter to convert to a"
+ " selection"));
+ }
+ iscissors->op = ISCISSORS_OP_IMPOSSIBLE;
+ }
+ }
+ else
+ {
+ switch (iscissors->state)
+ {
+ case WAITING:
+ if (proximity)
+ {
+ GdkModifierType snap_mask = gimp_get_extend_selection_mask ();
+ gchar *status;
+
+ status = gimp_suggest_modifiers (_("Click or Click-Drag to add a"
+ " point"),
+ snap_mask & ~state,
+ _("%s: disable auto-snap"),
+ NULL, NULL);
+ gimp_tool_replace_status (tool, display, "%s", status);
+ g_free (status);
+ }
+ iscissors->op = ISCISSORS_OP_ADD_POINT;
+ break;
+
+ default:
+ /* if NO_ACTION, keep parent's status bar message (selection tool) */
+ iscissors->op = ISCISSORS_OP_NONE;
+ break;
+ }
+ }
+}
+
+static void
+gimp_iscissors_tool_cursor_update (GimpTool *tool,
+ const GimpCoords *coords,
+ GdkModifierType state,
+ GimpDisplay *display)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (tool);
+ GimpCursorModifier modifier = GIMP_CURSOR_MODIFIER_NONE;
+
+ switch (iscissors->op)
+ {
+ case ISCISSORS_OP_SELECT:
+ {
+ GimpSelectionOptions *options;
+
+ options = GIMP_SELECTION_TOOL_GET_OPTIONS (tool);
+
+ /* Do not overwrite the modifiers for add, subtract, intersect */
+ if (options->operation == GIMP_CHANNEL_OP_REPLACE)
+ {
+ modifier = GIMP_CURSOR_MODIFIER_SELECT;
+ }
+ }
+ break;
+
+ case ISCISSORS_OP_MOVE_POINT:
+ modifier = GIMP_CURSOR_MODIFIER_MOVE;
+ break;
+
+ case ISCISSORS_OP_ADD_POINT:
+ modifier = GIMP_CURSOR_MODIFIER_PLUS;
+ break;
+
+ case ISCISSORS_OP_REMOVE_POINT:
+ modifier = GIMP_CURSOR_MODIFIER_MINUS;
+ break;
+
+ case ISCISSORS_OP_CONNECT:
+ modifier = GIMP_CURSOR_MODIFIER_JOIN;
+ break;
+
+ case ISCISSORS_OP_IMPOSSIBLE:
+ modifier = GIMP_CURSOR_MODIFIER_BAD;
+ break;
+
+ default:
+ break;
+ }
+
+ if (modifier != GIMP_CURSOR_MODIFIER_NONE)
+ {
+ gimp_tool_set_cursor (tool, display,
+ GIMP_CURSOR_MOUSE,
+ GIMP_TOOL_CURSOR_ISCISSORS,
+ modifier);
+ }
+ else
+ {
+ GIMP_TOOL_CLASS (parent_class)->cursor_update (tool, coords,
+ state, display);
+ }
+}
+
+static gboolean
+gimp_iscissors_tool_key_press (GimpTool *tool,
+ GdkEventKey *kevent,
+ GimpDisplay *display)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (tool);
+
+ if (display != tool->display)
+ return FALSE;
+
+ switch (kevent->keyval)
+ {
+ case GDK_KEY_BackSpace:
+ if (! iscissors->curve->closed &&
+ g_queue_peek_tail (iscissors->curve->segments))
+ {
+ ISegment *segment = g_queue_peek_tail (iscissors->curve->segments);
+
+ if (g_queue_get_length (iscissors->curve->segments) > 1)
+ {
+ gimp_draw_tool_pause (GIMP_DRAW_TOOL (tool));
+
+ gimp_iscissors_tool_push_undo (iscissors);
+ icurve_delete_segment (iscissors->curve, segment);
+ gimp_iscissors_tool_free_redo (iscissors);
+
+ gimp_draw_tool_resume (GIMP_DRAW_TOOL (tool));
+ }
+ else if (segment->x2 != segment->x1 || segment->y2 != segment->y1)
+ {
+ gimp_draw_tool_pause (GIMP_DRAW_TOOL (tool));
+
+ gimp_iscissors_tool_push_undo (iscissors);
+ segment->x2 = segment->x1;
+ segment->y2 = segment->y1;
+ g_ptr_array_remove_range (segment->points,
+ 0, segment->points->len);
+ gimp_iscissors_tool_free_redo (iscissors);
+
+ gimp_draw_tool_resume (GIMP_DRAW_TOOL (tool));
+ }
+ else
+ {
+ gimp_tool_control (tool, GIMP_TOOL_ACTION_HALT, display);
+ }
+ return TRUE;
+ }
+ return FALSE;
+
+ case GDK_KEY_Return:
+ case GDK_KEY_KP_Enter:
+ case GDK_KEY_ISO_Enter:
+ if (iscissors->curve->closed && iscissors->mask)
+ {
+ gimp_tool_control (tool, GIMP_TOOL_ACTION_COMMIT, display);
+ return TRUE;
+ }
+ return FALSE;
+
+ case GDK_KEY_Escape:
+ gimp_tool_control (tool, GIMP_TOOL_ACTION_HALT, display);
+ return TRUE;
+
+ default:
+ return FALSE;
+ }
+}
+
+static const gchar *
+gimp_iscissors_tool_can_undo (GimpTool *tool,
+ GimpDisplay *display)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (tool);
+
+ if (! iscissors->undo_stack)
+ return NULL;
+
+ return _("Modify Scissors Curve");
+}
+
+static const gchar *
+gimp_iscissors_tool_can_redo (GimpTool *tool,
+ GimpDisplay *display)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (tool);
+
+ if (! iscissors->redo_stack)
+ return NULL;
+
+ return _("Modify Scissors Curve");
+}
+
+static gboolean
+gimp_iscissors_tool_undo (GimpTool *tool,
+ GimpDisplay *display)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (tool);
+
+ gimp_draw_tool_pause (GIMP_DRAW_TOOL (tool));
+
+ iscissors->redo_stack = g_list_prepend (iscissors->redo_stack,
+ iscissors->curve);
+
+ iscissors->curve = iscissors->undo_stack->data;
+
+ iscissors->undo_stack = g_list_remove (iscissors->undo_stack,
+ iscissors->curve);
+
+ if (! iscissors->undo_stack)
+ {
+ iscissors->state = NO_ACTION;
+
+ gimp_draw_tool_stop (GIMP_DRAW_TOOL (tool));
+ }
+
+ gimp_draw_tool_resume (GIMP_DRAW_TOOL (tool));
+
+ return TRUE;
+}
+
+static gboolean
+gimp_iscissors_tool_redo (GimpTool *tool,
+ GimpDisplay *display)
+{
+ GimpIscissorsTool *iscissors = GIMP_ISCISSORS_TOOL (tool);
+
+ gimp_draw_tool_pause (GIMP_DRAW_TOOL (tool));
+
+ if (! iscissors->undo_stack)
+ {
+ iscissors->state = WAITING;
+
+ gimp_draw_tool_start (GIMP_DRAW_TOOL (tool), display);
+ }
+
+ iscissors->undo_stack = g_list_prepend (iscissors->undo_stack,
+ iscissors->curve);
+
+ iscissors->curve = iscissors->redo_stack->data;
+
+ iscissors->redo_stack = g_list_remove (iscissors->redo_stack,
+ iscissors->curve);
+
+ gimp_draw_tool_resume (GIMP_DRAW_TOOL (tool));
+
+ return TRUE;
+}
+
+static void
+gimp_iscissors_tool_push_undo (GimpIscissorsTool *iscissors)
+{
+ iscissors->undo_stack = g_list_prepend (iscissors->undo_stack,
+ icurve_copy (iscissors->curve));
+}
+
+static void
+gimp_iscissors_tool_pop_undo (GimpIscissorsTool *iscissors)
+{
+ icurve_free (iscissors->curve);
+ iscissors->curve = iscissors->undo_stack->data;
+
+ iscissors->undo_stack = g_list_remove (iscissors->undo_stack,
+ iscissors->curve);
+
+ if (! iscissors->undo_stack)
+ {
+ iscissors->state = NO_ACTION;
+
+ gimp_draw_tool_stop (GIMP_DRAW_TOOL (iscissors));
+ }
+}
+
+static void
+gimp_iscissors_tool_free_redo (GimpIscissorsTool *iscissors)
+{
+ g_list_free_full (iscissors->redo_stack,
+ (GDestroyNotify) icurve_free);
+ iscissors->redo_stack = NULL;
+
+ /* update the undo actions / menu items */
+ gimp_image_flush (gimp_display_get_image (GIMP_TOOL (iscissors)->display));
+}
+
+static void
+gimp_iscissors_tool_halt (GimpIscissorsTool *iscissors,
+ GimpDisplay *display)
+{
+ icurve_clear (iscissors->curve);
+
+ iscissors->segment1 = NULL;
+ iscissors->segment2 = NULL;
+ iscissors->state = NO_ACTION;
+
+ if (iscissors->undo_stack)
+ {
+ g_list_free_full (iscissors->undo_stack, (GDestroyNotify) icurve_free);
+ iscissors->undo_stack = NULL;
+ }
+
+ if (iscissors->redo_stack)
+ {
+ g_list_free_full (iscissors->redo_stack, (GDestroyNotify) icurve_free);
+ iscissors->redo_stack = NULL;
+ }
+
+ g_clear_object (&iscissors->gradient_map);
+ g_clear_object (&iscissors->mask);
+}
+
+static void
+gimp_iscissors_tool_commit (GimpIscissorsTool *iscissors,
+ GimpDisplay *display)
+{
+ GimpTool *tool = GIMP_TOOL (iscissors);
+ GimpSelectionOptions *options = GIMP_SELECTION_TOOL_GET_OPTIONS (tool);
+ GimpImage *image = gimp_display_get_image (display);
+
+ if (! iscissors->curve->closed)
+ {
+ ISegment *first = g_queue_peek_head (iscissors->curve->segments);
+ ISegment *last = g_queue_peek_tail (iscissors->curve->segments);
+
+ if (first && last && first != last)
+ {
+ ISegment *segment;
+
+ segment = icurve_append_segment (iscissors->curve,
+ last->x2,
+ last->y2,
+ first->x1,
+ first->y1);
+ icurve_close (iscissors->curve);
+ calculate_segment (iscissors, segment);
+
+ iscissors_convert (iscissors, display);
+ }
+ }
+
+ if (iscissors->curve->closed && iscissors->mask)
+ {
+ gimp_channel_select_channel (gimp_image_get_mask (image),
+ gimp_tool_get_undo_desc (tool),
+ iscissors->mask,
+ 0, 0,
+ options->operation,
+ options->feather,
+ options->feather_radius,
+ options->feather_radius);
+
+ gimp_image_flush (image);
+ }
+}
+
+
+/* XXX need some scan-conversion routines from somewhere. maybe. ? */
+
+static gint
+mouse_over_vertex (GimpIscissorsTool *iscissors,
+ gdouble x,
+ gdouble y)
+{
+ GList *list;
+ gint segments_found = 0;
+
+ /* traverse through the list, returning non-zero if the current cursor
+ * position is on an existing curve vertex. Set the segment1 and segment2
+ * variables to the two segments containing the vertex in question
+ */
+
+ iscissors->segment1 = iscissors->segment2 = NULL;
+
+ for (list = g_queue_peek_head_link (iscissors->curve->segments);
+ list;
+ list = g_list_next (list))
+ {
+ ISegment *segment = list->data;
+
+ if (gimp_draw_tool_on_handle (GIMP_DRAW_TOOL (iscissors),
+ GIMP_TOOL (iscissors)->display,
+ x, y,
+ GIMP_HANDLE_CIRCLE,
+ segment->x1, segment->y1,
+ GIMP_TOOL_HANDLE_SIZE_CIRCLE,
+ GIMP_TOOL_HANDLE_SIZE_CIRCLE,
+ GIMP_HANDLE_ANCHOR_CENTER))
+ {
+ iscissors->segment1 = segment;
+
+ if (segments_found++)
+ return segments_found;
+ }
+ else if (gimp_draw_tool_on_handle (GIMP_DRAW_TOOL (iscissors),
+ GIMP_TOOL (iscissors)->display,
+ x, y,
+ GIMP_HANDLE_CIRCLE,
+ segment->x2, segment->y2,
+ GIMP_TOOL_HANDLE_SIZE_CIRCLE,
+ GIMP_TOOL_HANDLE_SIZE_CIRCLE,
+ GIMP_HANDLE_ANCHOR_CENTER))
+ {
+ iscissors->segment2 = segment;
+
+ if (segments_found++)
+ return segments_found;
+ }
+ }
+
+ return segments_found;
+}
+
+static gboolean
+clicked_on_vertex (GimpIscissorsTool *iscissors,
+ gdouble x,
+ gdouble y)
+{
+ gint segments_found = mouse_over_vertex (iscissors, x, y);
+
+ if (segments_found > 1)
+ {
+ gimp_iscissors_tool_push_undo (iscissors);
+
+ return TRUE;
+ }
+
+ /* if only one segment was found, the segments are unconnected, and
+ * the user only wants to move either the first or last point
+ * disallow this for now.
+ */
+ if (segments_found == 1)
+ return FALSE;
+
+ return clicked_on_segment (iscissors, x, y);
+}
+
+
+static GList *
+mouse_over_segment (GimpIscissorsTool *iscissors,
+ gdouble x,
+ gdouble y)
+{
+ GList *list;
+
+ /* traverse through the list, returning the curve segment's list element
+ * if the current cursor position is on a curve...
+ */
+ for (list = g_queue_peek_head_link (iscissors->curve->segments);
+ list;
+ list = g_list_next (list))
+ {
+ ISegment *segment = list->data;
+ gpointer *pt;
+ gint len;
+
+ if (! segment->points)
+ continue;
+
+ pt = segment->points->pdata;
+ len = segment->points->len;
+
+ while (len--)
+ {
+ guint32 coords = GPOINTER_TO_INT (*pt);
+ gint tx, ty;
+
+ pt++;
+ tx = coords & 0x0000ffff;
+ ty = coords >> 16;
+
+ /* Is the specified point close enough to the segment? */
+ if (gimp_draw_tool_calc_distance_square (GIMP_DRAW_TOOL (iscissors),
+ GIMP_TOOL (iscissors)->display,
+ tx, ty,
+ x, y) < SQR (GIMP_TOOL_HANDLE_SIZE_CIRCLE / 2))
+ {
+ return list;
+ }
+ }
+ }
+
+ return NULL;
+}
+
+static gboolean
+clicked_on_segment (GimpIscissorsTool *iscissors,
+ gdouble x,
+ gdouble y)
+{
+ GList *list = mouse_over_segment (iscissors, x, y);
+
+ /* traverse through the list, getting back the curve segment's list
+ * element if the current cursor position is on a segment...
+ * If this occurs, replace the segment with two new segments,
+ * separated by a new vertex.
+ */
+
+ if (list)
+ {
+ ISegment *segment = list->data;
+ ISegment *new_segment;
+
+ gimp_iscissors_tool_push_undo (iscissors);
+
+ new_segment = icurve_insert_segment (iscissors->curve,
+ list,
+ iscissors->x,
+ iscissors->y,
+ segment->x2,
+ segment->y2);
+
+ iscissors->segment1 = new_segment;
+ iscissors->segment2 = segment;
+
+ return TRUE;
+ }
+
+ return FALSE;
+}
+
+
+static void
+calculate_segment (GimpIscissorsTool *iscissors,
+ ISegment *segment)
+{
+ GimpDisplay *display = GIMP_TOOL (iscissors)->display;
+ GimpPickable *pickable = GIMP_PICKABLE (gimp_display_get_image (display));
+ gint width;
+ gint height;
+ gint xs, ys, xe, ye;
+ gint x1, y1, x2, y2;
+ gint ewidth, eheight;
+
+ /* Initialise the gradient map buffer for this pickable if we don't
+ * already have one.
+ */
+ if (! iscissors->gradient_map)
+ iscissors->gradient_map = gradient_map_new (pickable);
+
+ width = gegl_buffer_get_width (iscissors->gradient_map);
+ height = gegl_buffer_get_height (iscissors->gradient_map);
+
+ /* Calculate the lowest cost path from one vertex to the next as specified
+ * by the parameter "segment".
+ * Here are the steps:
+ * 1) Calculate the appropriate working area for this operation
+ * 2) Allocate a temp buf for the dynamic programming array
+ * 3) Run the dynamic programming algorithm to find the optimal path
+ * 4) Translate the optimal path into pixels in the isegment data
+ * structure.
+ */
+
+ /* Get the bounding box */
+ xs = CLAMP (segment->x1, 0, width - 1);
+ ys = CLAMP (segment->y1, 0, height - 1);
+ xe = CLAMP (segment->x2, 0, width - 1);
+ ye = CLAMP (segment->y2, 0, height - 1);
+ x1 = MIN (xs, xe);
+ y1 = MIN (ys, ye);
+ x2 = MAX (xs, xe) + 1; /* +1 because if xe = 199 & xs = 0, x2 - x1, width = 200 */
+ y2 = MAX (ys, ye) + 1;
+
+ /* expand the boundaries past the ending points by
+ * some percentage of width and height. This serves the following purpose:
+ * It gives the algorithm more area to search so better solutions
+ * are found. This is particularly helpful in finding "bumps" which
+ * fall outside the bounding box represented by the start and end
+ * coordinates of the "segment".
+ */
+ ewidth = (x2 - x1) * EXTEND_BY + FIXED;
+ eheight = (y2 - y1) * EXTEND_BY + FIXED;
+
+ if (xe >= xs)
+ x2 += CLAMP (ewidth, 0, width - x2);
+ else
+ x1 -= CLAMP (ewidth, 0, x1);
+
+ if (ye >= ys)
+ y2 += CLAMP (eheight, 0, height - y2);
+ else
+ y1 -= CLAMP (eheight, 0, y1);
+
+ /* blow away any previous points list we might have */
+ if (segment->points)
+ {
+ g_ptr_array_free (segment->points, TRUE);
+ segment->points = NULL;
+ }
+
+ if ((x2 - x1) && (y2 - y1))
+ {
+ /* If the bounding box has width and height... */
+
+ GimpTempBuf *dp_buf; /* dynamic programming buffer */
+ gint dp_width = (x2 - x1);
+ gint dp_height = (y2 - y1);
+
+ dp_buf = gimp_temp_buf_new (dp_width, dp_height,
+ babl_format ("Y u32"));
+
+ /* find the optimal path of pixels from (x1, y1) to (x2, y2) */
+ find_optimal_path (iscissors->gradient_map, dp_buf,
+ x1, y1, x2, y2, xs, ys);
+
+ /* get a list of the pixels in the optimal path */
+ segment->points = plot_pixels (dp_buf, x1, y1, xs, ys, xe, ye);
+
+ gimp_temp_buf_unref (dp_buf);
+ }
+ else if ((x2 - x1) == 0)
+ {
+ /* If the bounding box has no width */
+
+ /* plot a vertical line */
+ gint y = ys;
+ gint dir = (ys > ye) ? -1 : 1;
+
+ segment->points = g_ptr_array_new ();
+ while (y != ye)
+ {
+ g_ptr_array_add (segment->points, GINT_TO_POINTER ((y << 16) + xs));
+ y += dir;
+ }
+ }
+ else if ((y2 - y1) == 0)
+ {
+ /* If the bounding box has no height */
+
+ /* plot a horizontal line */
+ gint x = xs;
+ gint dir = (xs > xe) ? -1 : 1;
+
+ segment->points = g_ptr_array_new ();
+ while (x != xe)
+ {
+ g_ptr_array_add (segment->points, GINT_TO_POINTER ((ys << 16) + x));
+ x += dir;
+ }
+ }
+}
+
+
+/* badly need to get a replacement - this is _way_ too expensive */
+static gboolean
+gradient_map_value (GeglSampler *map_sampler,
+ const GeglRectangle *map_extent,
+ gint x,
+ gint y,
+ guint8 *grad,
+ guint8 *dir)
+{
+ if (x >= map_extent->x &&
+ y >= map_extent->y &&
+ x < map_extent->width &&
+ y < map_extent->height)
+ {
+ guint8 sample[2];
+
+ gegl_sampler_get (map_sampler, x, y, NULL, sample, GEGL_ABYSS_NONE);
+
+ *grad = sample[0];
+ *dir = sample[1];
+
+ return TRUE;
+ }
+
+ return FALSE;
+}
+
+static gint
+calculate_link (GeglSampler *map_sampler,
+ const GeglRectangle *map_extent,
+ gint x,
+ gint y,
+ guint32 pixel,
+ gint link)
+{
+ gint value = 0;
+ guint8 grad1, dir1, grad2, dir2;
+
+ if (! gradient_map_value (map_sampler, map_extent, x, y, &grad1, &dir1))
+ {
+ grad1 = 0;
+ dir1 = 255;
+ }
+
+ /* Convert the gradient into a cost: large gradients are good, and
+ * so have low cost. */
+ grad1 = 255 - grad1;
+
+ /* calculate the contribution of the gradient magnitude */
+ if (link > 1)
+ value += diagonal_weight[grad1] * OMEGA_G;
+ else
+ value += grad1 * OMEGA_G;
+
+ /* calculate the contribution of the gradient direction */
+ x += (gint8)(pixel & 0xff);
+ y += (gint8)((pixel & 0xff00) >> 8);
+
+ if (! gradient_map_value (map_sampler, map_extent, x, y, &grad2, &dir2))
+ {
+ grad2 = 0;
+ dir2 = 255;
+ }
+
+ value +=
+ (direction_value[dir1][link] + direction_value[dir2][link]) * OMEGA_D;
+
+ return value;
+}
+
+
+static GPtrArray *
+plot_pixels (GimpTempBuf *dp_buf,
+ gint x1,
+ gint y1,
+ gint xs,
+ gint ys,
+ gint xe,
+ gint ye)
+{
+ gint x, y;
+ guint32 coords;
+ gint link;
+ gint width = gimp_temp_buf_get_width (dp_buf);
+ guint *data;
+ GPtrArray *list;
+
+ /* Start the data pointer at the correct location */
+ data = (guint *) gimp_temp_buf_get_data (dp_buf) + (ye - y1) * width + (xe - x1);
+
+ x = xe;
+ y = ye;
+
+ list = g_ptr_array_new ();
+
+ while (TRUE)
+ {
+ coords = (y << 16) + x;
+ g_ptr_array_add (list, GINT_TO_POINTER (coords));
+
+ link = PIXEL_DIR (*data);
+ if (link == SEED_POINT)
+ return list;
+
+ x += move[link][0];
+ y += move[link][1];
+ data += move[link][1] * width + move[link][0];
+ }
+
+ /* won't get here */
+ return NULL;
+}
+
+
+#define PACK(x, y) ((((y) & 0xff) << 8) | ((x) & 0xff))
+#define OFFSET(pixel) ((gint8)((pixel) & 0xff) + \
+ ((gint8)(((pixel) & 0xff00) >> 8)) * \
+ gimp_temp_buf_get_width (dp_buf))
+
+static void
+find_optimal_path (GeglBuffer *gradient_map,
+ GimpTempBuf *dp_buf,
+ gint x1,
+ gint y1,
+ gint x2,
+ gint y2,
+ gint xs,
+ gint ys)
+{
+ GeglSampler *map_sampler;
+ const GeglRectangle *map_extent;
+ gint i, j, k;
+ gint x, y;
+ gint link;
+ gint linkdir;
+ gint dirx, diry;
+ gint min_cost;
+ gint new_cost;
+ gint offset;
+ gint cum_cost[8];
+ gint link_cost[8];
+ gint pixel_cost[8];
+ guint32 pixel[8];
+ guint32 *data;
+ guint32 *d;
+ gint dp_buf_width = gimp_temp_buf_get_width (dp_buf);
+ gint dp_buf_height = gimp_temp_buf_get_height (dp_buf);
+
+ /* initialize the gradient map sampler and extent */
+ map_sampler = gegl_buffer_sampler_new (gradient_map,
+ gegl_buffer_get_format (gradient_map),
+ GEGL_SAMPLER_NEAREST);
+ map_extent = gegl_buffer_get_extent (gradient_map);
+
+ /* initialize the dynamic programming buffer */
+ data = (guint32 *) gimp_temp_buf_data_clear (dp_buf);
+
+ /* what directions are we filling the array in according to? */
+ dirx = (xs - x1 == 0) ? 1 : -1;
+ diry = (ys - y1 == 0) ? 1 : -1;
+ linkdir = (dirx * diry);
+
+ y = ys;
+
+ for (i = 0; i < dp_buf_height; i++)
+ {
+ x = xs;
+
+ d = data + (y-y1) * dp_buf_width + (x-x1);
+
+ for (j = 0; j < dp_buf_width; j++)
+ {
+ min_cost = G_MAXINT;
+
+ /* pixel[] array encodes how to get to a neighbour, if possible.
+ * 0 means no connection (eg edge).
+ * Rest packed as bottom two bytes: y offset then x offset.
+ * Initially, we assume we can't get anywhere.
+ */
+ for (k = 0; k < 8; k++)
+ pixel[k] = 0;
+
+ /* Find the valid neighboring pixels */
+ /* the previous pixel */
+ if (j)
+ pixel[((dirx == 1) ? 4 : 0)] = PACK (-dirx, 0);
+
+ /* the previous row of pixels */
+ if (i)
+ {
+ pixel[((diry == 1) ? 5 : 1)] = PACK (0, -diry);
+
+ link = (linkdir == 1) ? 3 : 2;
+ if (j)
+ pixel[((diry == 1) ? (link + 4) : link)] = PACK (-dirx, -diry);
+
+ link = (linkdir == 1) ? 2 : 3;
+ if (j != dp_buf_width - 1)
+ pixel[((diry == 1) ? (link + 4) : link)] = PACK (dirx, -diry);
+ }
+
+ /* find the minimum cost of going through each neighbor to reach the
+ * seed point...
+ */
+ link = -1;
+ for (k = 0; k < 8; k ++)
+ if (pixel[k])
+ {
+ link_cost[k] = calculate_link (map_sampler, map_extent,
+ xs + j*dirx, ys + i*diry,
+ pixel [k],
+ ((k > 3) ? k - 4 : k));
+ offset = OFFSET (pixel [k]);
+ pixel_cost[k] = PIXEL_COST (d[offset]);
+ cum_cost[k] = pixel_cost[k] + link_cost[k];
+ if (cum_cost[k] < min_cost)
+ {
+ min_cost = cum_cost[k];
+ link = k;
+ }
+ }
+
+ /* If anything can be done... */
+ if (link >= 0)
+ {
+ /* set the cumulative cost of this pixel and the new direction
+ */
+ *d = (cum_cost[link] << 8) + link;
+
+ /* possibly change the links from the other pixels to this pixel...
+ * these changes occur if a neighboring pixel will receive a lower
+ * cumulative cost by going through this pixel.
+ */
+ for (k = 0; k < 8; k ++)
+ if (pixel[k] && k != link)
+ {
+ /* if the cumulative cost at the neighbor is greater than
+ * the cost through the link to the current pixel, change the
+ * neighbor's link to point to the current pixel.
+ */
+ new_cost = link_cost[k] + cum_cost[link];
+ if (pixel_cost[k] > new_cost)
+ {
+ /* reverse the link direction /--------------------\ */
+ offset = OFFSET (pixel[k]);
+ d[offset] = (new_cost << 8) + ((k > 3) ? k - 4 : k + 4);
+ }
+ }
+ }
+ /* Set the seed point */
+ else if (!i && !j)
+ {
+ *d = SEED_POINT;
+ }
+
+ /* increment the data pointer and the x counter */
+ d += dirx;
+ x += dirx;
+ }
+
+ /* increment the y counter */
+ y += diry;
+ }
+
+ g_object_unref (map_sampler);
+}
+
+static GeglBuffer *
+gradient_map_new (GimpPickable *pickable)
+{
+ GeglBuffer *buffer;
+ GeglTileHandler *handler;
+
+ buffer = gimp_pickable_get_buffer (pickable);
+
+ buffer = gegl_buffer_new (GEGL_RECTANGLE (0, 0,
+ gegl_buffer_get_width (buffer),
+ gegl_buffer_get_height (buffer)),
+ babl_format_n (babl_type ("u8"), 2));
+
+ handler = gimp_tile_handler_iscissors_new (pickable);
+
+ gimp_tile_handler_validate_assign (GIMP_TILE_HANDLER_VALIDATE (handler),
+ buffer);
+
+ gimp_tile_handler_validate_invalidate (GIMP_TILE_HANDLER_VALIDATE (handler),
+ GEGL_RECTANGLE (0, 0,
+ gegl_buffer_get_width (buffer),
+ gegl_buffer_get_height (buffer)));
+
+ g_object_unref (handler);
+
+ return buffer;
+}
+
+static void
+find_max_gradient (GimpIscissorsTool *iscissors,
+ GimpPickable *pickable,
+ gint *x,
+ gint *y)
+{
+ GeglBufferIterator *iter;
+ GeglRectangle *roi;
+ gint width;
+ gint height;
+ gint radius;
+ gint cx, cy;
+ gint x1, y1, x2, y2;
+ gfloat max_gradient;
+
+ /* Initialise the gradient map buffer for this pickable if we don't
+ * already have one.
+ */
+ if (! iscissors->gradient_map)
+ iscissors->gradient_map = gradient_map_new (pickable);
+
+ width = gegl_buffer_get_width (iscissors->gradient_map);
+ height = gegl_buffer_get_height (iscissors->gradient_map);
+
+ radius = GRADIENT_SEARCH >> 1;
+
+ /* calculate the extent of the search */
+ cx = CLAMP (*x, 0, width);
+ cy = CLAMP (*y, 0, height);
+ x1 = CLAMP (cx - radius, 0, width);
+ y1 = CLAMP (cy - radius, 0, height);
+ x2 = CLAMP (cx + radius, 0, width);
+ y2 = CLAMP (cy + radius, 0, height);
+ /* calculate the factor to multiply the distance from the cursor by */
+
+ max_gradient = 0;
+ *x = cx;
+ *y = cy;
+
+ iter = gegl_buffer_iterator_new (iscissors->gradient_map,
+ GEGL_RECTANGLE (x1, y1, x2 - x1, y2 - y1),
+ 0, NULL,
+ GEGL_ACCESS_READ, GEGL_ABYSS_NONE, 1);
+ roi = &iter->items[0].roi;
+
+ while (gegl_buffer_iterator_next (iter))
+ {
+ guint8 *data = iter->items[0].data;
+ gint endx = roi->x + roi->width;
+ gint endy = roi->y + roi->height;
+ gint i, j;
+
+ for (i = roi->y; i < endy; i++)
+ {
+ const guint8 *gradient = data + 2 * roi->width * (i - roi->y);
+
+ for (j = roi->x; j < endx; j++)
+ {
+ gfloat g = *gradient;
+
+ gradient += COST_WIDTH;
+
+ g *= distance_weights [(i - y1) * GRADIENT_SEARCH + (j - x1)];
+
+ if (g > max_gradient)
+ {
+ max_gradient = g;
+
+ *x = j;
+ *y = i;
+ }
+ }
+ }
+ }
+}
+
+static ISegment *
+isegment_new (gint x1,
+ gint y1,
+ gint x2,
+ gint y2)
+{
+ ISegment *segment = g_slice_new0 (ISegment);
+
+ segment->x1 = x1;
+ segment->y1 = y1;
+ segment->x2 = x2;
+ segment->y2 = y2;
+
+ return segment;
+}
+
+static ISegment *
+isegment_copy (ISegment *segment)
+{
+ ISegment *copy = isegment_new (segment->x1,
+ segment->y1,
+ segment->x2,
+ segment->y2);
+
+ if (segment->points)
+ {
+ gint i;
+
+ copy->points = g_ptr_array_sized_new (segment->points->len);
+
+ for (i = 0; i < segment->points->len; i++)
+ {
+ gpointer value = g_ptr_array_index (segment->points, i);
+
+ g_ptr_array_add (copy->points, value);
+ }
+ }
+
+ return copy;
+}
+
+static void
+isegment_free (ISegment *segment)
+{
+ if (segment->points)
+ g_ptr_array_free (segment->points, TRUE);
+
+ g_slice_free (ISegment, segment);
+}
+
+static ICurve *
+icurve_new (void)
+{
+ ICurve *curve = g_slice_new0 (ICurve);
+
+ curve->segments = g_queue_new ();
+ curve->first_point = TRUE;
+
+ return curve;
+}
+
+static ICurve *
+icurve_copy (ICurve *curve)
+{
+ ICurve *copy = icurve_new ();
+ GList *link;
+
+ for (link = g_queue_peek_head_link (curve->segments);
+ link;
+ link = g_list_next (link))
+ {
+ g_queue_push_tail (copy->segments, isegment_copy (link->data));
+ }
+
+ copy->first_point = curve->first_point;
+ copy->closed = curve->closed;
+
+ return copy;
+}
+
+static void
+icurve_clear (ICurve *curve)
+{
+ while (! g_queue_is_empty (curve->segments))
+ isegment_free (g_queue_pop_head (curve->segments));
+
+ curve->first_point = TRUE;
+ curve->closed = FALSE;
+}
+
+static void
+icurve_free (ICurve *curve)
+{
+ g_queue_free_full (curve->segments, (GDestroyNotify) isegment_free);
+
+ g_slice_free (ICurve, curve);
+}
+
+static ISegment *
+icurve_append_segment (ICurve *curve,
+ gint x1,
+ gint y1,
+ gint x2,
+ gint y2)
+{
+ ISegment *segment = isegment_new (x1, y1, x2, y2);
+
+ g_queue_push_tail (curve->segments, segment);
+
+ return segment;
+}
+
+static ISegment *
+icurve_insert_segment (ICurve *curve,
+ GList *sibling,
+ gint x1,
+ gint y1,
+ gint x2,
+ gint y2)
+{
+ ISegment *segment = sibling->data;
+ ISegment *new_segment;
+
+ new_segment = isegment_new (x1, y1, x2, y2);
+
+ segment->x2 = x1;
+ segment->y2 = y1;
+
+ g_queue_insert_after (curve->segments, sibling, new_segment);
+
+ return new_segment;
+}
+
+static void
+icurve_delete_segment (ICurve *curve,
+ ISegment *segment)
+{
+ GList *link = g_queue_find (curve->segments, segment);
+ ISegment *next_segment = NULL;
+
+ if (link->next)
+ next_segment = link->next->data;
+ else if (curve->closed)
+ next_segment = g_queue_peek_head (curve->segments);
+
+ if (next_segment)
+ {
+ next_segment->x1 = segment->x1;
+ next_segment->y1 = segment->y1;
+ }
+
+ g_queue_remove (curve->segments, segment);
+ isegment_free (segment);
+}
+
+static void
+icurve_close (ICurve *curve)
+{
+ ISegment *first = g_queue_peek_head (curve->segments);
+ ISegment *last = g_queue_peek_tail (curve->segments);
+
+ last->x2 = first->x1;
+ last->y2 = first->y1;
+
+ curve->closed = TRUE;
+}
+
+static GimpScanConvert *
+icurve_create_scan_convert (ICurve *curve)
+{
+ GimpScanConvert *sc;
+ GList *list;
+ GimpVector2 *points;
+ guint n_total_points = 0;
+
+ sc = gimp_scan_convert_new ();
+
+ for (list = g_queue_peek_tail_link (curve->segments);
+ list;
+ list = g_list_previous (list))
+ {
+ ISegment *segment = list->data;
+
+ n_total_points += segment->points->len;
+ }
+
+ points = g_new (GimpVector2, n_total_points);
+ n_total_points = 0;
+
+ /* go over the segments in reverse order, adding the points we have */
+ for (list = g_queue_peek_tail_link (curve->segments);
+ list;
+ list = g_list_previous (list))
+ {
+ ISegment *segment = list->data;
+ guint n_points;
+ gint i;
+
+ n_points = segment->points->len;
+
+ for (i = 0; i < n_points; i++)
+ {
+ guint32 packed = GPOINTER_TO_INT (g_ptr_array_index (segment->points,
+ i));
+
+ points[n_total_points + i].x = packed & 0x0000ffff;
+ points[n_total_points + i].y = packed >> 16;
+ }
+
+ n_total_points += n_points;
+ }
+
+ gimp_scan_convert_add_polyline (sc, n_total_points, points, TRUE);
+ g_free (points);
+
+ return sc;
+}