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-rw-r--r--app/display/gimpdisplayshell-scroll.c529
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diff --git a/app/display/gimpdisplayshell-scroll.c b/app/display/gimpdisplayshell-scroll.c
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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/>.
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <math.h>
+
+#include <gegl.h>
+#include <gtk/gtk.h>
+
+#include "libgimpmath/gimpmath.h"
+
+#include "display-types.h"
+
+#include "config/gimpdisplayconfig.h"
+
+#include "core/gimpimage.h"
+
+#include "gimpcanvas.h"
+#include "gimpdisplay.h"
+#include "gimpdisplay-foreach.h"
+#include "gimpdisplayshell.h"
+#include "gimpdisplayshell-expose.h"
+#include "gimpdisplayshell-rotate.h"
+#include "gimpdisplayshell-rulers.h"
+#include "gimpdisplayshell-scale.h"
+#include "gimpdisplayshell-scroll.h"
+#include "gimpdisplayshell-scrollbars.h"
+#include "gimpdisplayshell-transform.h"
+
+
+#define OVERPAN_FACTOR 0.5
+
+
+/**
+ * gimp_display_shell_scroll:
+ * @shell:
+ * @x_offset:
+ * @y_offset:
+ *
+ * This function scrolls the image in the shell's viewport. It does
+ * actual scrolling of the pixels, so only the newly scrolled-in parts
+ * are freshly redrawn.
+ *
+ * Use it for incremental actual panning.
+ **/
+void
+gimp_display_shell_scroll (GimpDisplayShell *shell,
+ gint x_offset,
+ gint y_offset)
+{
+ gint old_x;
+ gint old_y;
+
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ if (x_offset == 0 && y_offset == 0)
+ return;
+
+ old_x = shell->offset_x;
+ old_y = shell->offset_y;
+
+ /* freeze the active tool */
+ gimp_display_shell_pause (shell);
+
+ shell->offset_x += x_offset;
+ shell->offset_y += y_offset;
+
+ gimp_display_shell_scroll_clamp_and_update (shell);
+
+ /* the actual changes in offset */
+ x_offset = (shell->offset_x - old_x);
+ y_offset = (shell->offset_y - old_y);
+
+ if (x_offset || y_offset)
+ {
+ gimp_display_shell_scrolled (shell);
+
+ gimp_overlay_box_scroll (GIMP_OVERLAY_BOX (shell->canvas),
+ -x_offset, -y_offset);
+
+ }
+
+ /* re-enable the active tool */
+ gimp_display_shell_resume (shell);
+}
+
+/**
+ * gimp_display_shell_scroll_set_offsets:
+ * @shell:
+ * @offset_x:
+ * @offset_y:
+ *
+ * This function scrolls the image in the shell's viewport. It redraws
+ * the entire canvas.
+ *
+ * Use it for setting the scroll offset on freshly scaled images or
+ * when the window is resized. For panning, use
+ * gimp_display_shell_scroll().
+ **/
+void
+gimp_display_shell_scroll_set_offset (GimpDisplayShell *shell,
+ gint offset_x,
+ gint offset_y)
+{
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ if (shell->offset_x == offset_x &&
+ shell->offset_y == offset_y)
+ return;
+
+ gimp_display_shell_scale_save_revert_values (shell);
+
+ /* freeze the active tool */
+ gimp_display_shell_pause (shell);
+
+ shell->offset_x = offset_x;
+ shell->offset_y = offset_y;
+
+ gimp_display_shell_scroll_clamp_and_update (shell);
+
+ gimp_display_shell_scrolled (shell);
+
+ gimp_display_shell_expose_full (shell);
+
+ /* re-enable the active tool */
+ gimp_display_shell_resume (shell);
+}
+
+/**
+ * gimp_display_shell_scroll_clamp_and_update:
+ * @shell:
+ *
+ * Helper function for calling two functions that are commonly called
+ * in pairs.
+ **/
+void
+gimp_display_shell_scroll_clamp_and_update (GimpDisplayShell *shell)
+{
+ GimpImage *image;
+
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ image = gimp_display_get_image (shell->display);
+
+ if (image)
+ {
+ if (! shell->show_all)
+ {
+ gint bounds_x;
+ gint bounds_y;
+ gint bounds_width;
+ gint bounds_height;
+ gint min_offset_x;
+ gint max_offset_x;
+ gint min_offset_y;
+ gint max_offset_y;
+ gint offset_x;
+ gint offset_y;
+
+ gimp_display_shell_rotate_update_transform (shell);
+
+ gimp_display_shell_scale_get_image_bounds (shell,
+ &bounds_x,
+ &bounds_y,
+ &bounds_width,
+ &bounds_height);
+
+ if (shell->disp_width < bounds_width)
+ {
+ min_offset_x = bounds_x -
+ shell->disp_width * OVERPAN_FACTOR;
+ max_offset_x = bounds_x + bounds_width -
+ shell->disp_width * (1.0 - OVERPAN_FACTOR);
+ }
+ else
+ {
+ gint overpan_amount;
+
+ overpan_amount = shell->disp_width -
+ bounds_width * (1.0 - OVERPAN_FACTOR);
+
+ min_offset_x = bounds_x -
+ overpan_amount;
+ max_offset_x = bounds_x + bounds_width - shell->disp_width +
+ overpan_amount;
+ }
+
+ if (shell->disp_height < bounds_height)
+ {
+ min_offset_y = bounds_y -
+ shell->disp_height * OVERPAN_FACTOR;
+ max_offset_y = bounds_y + bounds_height -
+ shell->disp_height * (1.0 - OVERPAN_FACTOR);
+ }
+ else
+ {
+ gint overpan_amount;
+
+ overpan_amount = shell->disp_height -
+ bounds_height * (1.0 - OVERPAN_FACTOR);
+
+ min_offset_y = bounds_y -
+ overpan_amount;
+ max_offset_y = bounds_y + bounds_height +
+ overpan_amount - shell->disp_height;
+ }
+
+ /* Clamp */
+
+ offset_x = CLAMP (shell->offset_x, min_offset_x, max_offset_x);
+ offset_y = CLAMP (shell->offset_y, min_offset_y, max_offset_y);
+
+ if (offset_x != shell->offset_x || offset_y != shell->offset_y)
+ {
+ shell->offset_x = offset_x;
+ shell->offset_y = offset_y;
+
+ gimp_display_shell_rotate_update_transform (shell);
+ }
+
+ /* Set scrollbar stepper sensitiity */
+
+ gimp_display_shell_scrollbars_update_steppers (shell,
+ min_offset_x,
+ max_offset_x,
+ min_offset_y,
+ max_offset_y);
+ }
+ else
+ {
+ /* Set scrollbar stepper sensitiity */
+
+ gimp_display_shell_scrollbars_update_steppers (shell,
+ G_MININT,
+ G_MAXINT,
+ G_MININT,
+ G_MAXINT);
+ }
+ }
+ else
+ {
+ shell->offset_x = 0;
+ shell->offset_y = 0;
+ }
+
+ gimp_display_shell_scrollbars_update (shell);
+ gimp_display_shell_rulers_update (shell);
+}
+
+/**
+ * gimp_display_shell_scroll_unoverscrollify:
+ * @shell:
+ * @in_offset_x:
+ * @in_offset_y:
+ * @out_offset_x:
+ * @out_offset_y:
+ *
+ * Takes a scroll offset and returns the offset that will not result
+ * in a scroll beyond the image border. If the image is already
+ * overscrolled, the return value is 0 for that given axis.
+ **/
+void
+gimp_display_shell_scroll_unoverscrollify (GimpDisplayShell *shell,
+ gint in_offset_x,
+ gint in_offset_y,
+ gint *out_offset_x,
+ gint *out_offset_y)
+{
+ gint sw, sh;
+ gint out_offset_x_dummy, out_offset_y_dummy;
+
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ if (! out_offset_x) out_offset_x = &out_offset_x_dummy;
+ if (! out_offset_y) out_offset_y = &out_offset_y_dummy;
+
+ *out_offset_x = in_offset_x;
+ *out_offset_y = in_offset_y;
+
+ if (! shell->show_all)
+ {
+ gimp_display_shell_scale_get_image_size (shell, &sw, &sh);
+
+ if (in_offset_x < 0)
+ {
+ *out_offset_x = MAX (in_offset_x,
+ MIN (0, 0 - shell->offset_x));
+ }
+ else if (in_offset_x > 0)
+ {
+ gint min_offset = sw - shell->disp_width;
+
+ *out_offset_x = MIN (in_offset_x,
+ MAX (0, min_offset - shell->offset_x));
+ }
+
+ if (in_offset_y < 0)
+ {
+ *out_offset_y = MAX (in_offset_y,
+ MIN (0, 0 - shell->offset_y));
+ }
+ else if (in_offset_y > 0)
+ {
+ gint min_offset = sh - shell->disp_height;
+
+ *out_offset_y = MIN (in_offset_y,
+ MAX (0, min_offset - shell->offset_y));
+ }
+ }
+}
+
+/**
+ * gimp_display_shell_scroll_center_image_xy:
+ * @shell:
+ * @image_x:
+ * @image_y:
+ *
+ * Center the viewport around the passed image coordinate
+ **/
+void
+gimp_display_shell_scroll_center_image_xy (GimpDisplayShell *shell,
+ gdouble image_x,
+ gdouble image_y)
+{
+ gint viewport_x;
+ gint viewport_y;
+
+ gimp_display_shell_transform_xy (shell,
+ image_x, image_y,
+ &viewport_x, &viewport_y);
+
+ gimp_display_shell_scroll (shell,
+ viewport_x - shell->disp_width / 2,
+ viewport_y - shell->disp_height / 2);
+}
+
+/**
+ * gimp_display_shell_scroll_center_image:
+ * @shell:
+ * @horizontally:
+ * @vertically:
+ *
+ * Centers the image in the display shell on the desired axes.
+ **/
+void
+gimp_display_shell_scroll_center_image (GimpDisplayShell *shell,
+ gboolean horizontally,
+ gboolean vertically)
+{
+ gint image_x;
+ gint image_y;
+ gint image_width;
+ gint image_height;
+ gint center_x;
+ gint center_y;
+ gint offset_x = 0;
+ gint offset_y = 0;
+
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ if (! shell->display ||
+ ! gimp_display_get_image (shell->display) ||
+ (! vertically && ! horizontally))
+ return;
+
+ gimp_display_shell_scale_get_image_bounds (shell,
+ &image_x, &image_y,
+ &image_width, &image_height);
+
+ if (shell->disp_width > image_width)
+ {
+ image_x -= (shell->disp_width - image_width) / 2;
+ image_width = shell->disp_width;
+ }
+
+ if (shell->disp_height > image_height)
+ {
+ image_y -= (shell->disp_height - image_height) / 2;
+ image_height = shell->disp_height;
+ }
+
+ center_x = image_x + image_width / 2;
+ center_y = image_y + image_height / 2;
+
+ if (horizontally)
+ offset_x = center_x - shell->disp_width / 2 - shell->offset_x;
+
+ if (vertically)
+ offset_y = center_y - shell->disp_height / 2 - shell->offset_y;
+
+ gimp_display_shell_scroll (shell, offset_x, offset_y);
+}
+
+/**
+ * gimp_display_shell_scroll_center_image:
+ * @shell:
+ * @horizontally:
+ * @vertically:
+ *
+ * Centers the image content in the display shell on the desired axes.
+ **/
+void
+gimp_display_shell_scroll_center_content (GimpDisplayShell *shell,
+ gboolean horizontally,
+ gboolean vertically)
+{
+ gint content_x;
+ gint content_y;
+ gint content_width;
+ gint content_height;
+ gint center_x;
+ gint center_y;
+ gint offset_x = 0;
+ gint offset_y = 0;
+
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ if (! shell->display ||
+ ! gimp_display_get_image (shell->display) ||
+ (! vertically && ! horizontally))
+ return;
+
+ if (! gimp_display_shell_get_infinite_canvas (shell))
+ {
+ gimp_display_shell_scale_get_image_bounds (shell,
+ &content_x,
+ &content_y,
+ &content_width,
+ &content_height);
+ }
+ else
+ {
+ gimp_display_shell_scale_get_image_bounding_box (shell,
+ &content_x,
+ &content_y,
+ &content_width,
+ &content_height);
+ }
+
+ if (shell->disp_width > content_width)
+ {
+ content_x -= (shell->disp_width - content_width) / 2;
+ content_width = shell->disp_width;
+ }
+
+ if (shell->disp_height > content_height)
+ {
+ content_y -= (shell->disp_height - content_height) / 2;
+ content_height = shell->disp_height;
+ }
+
+ center_x = content_x + content_width / 2;
+ center_y = content_y + content_height / 2;
+
+ if (horizontally)
+ offset_x = center_x - shell->disp_width / 2 - shell->offset_x;
+
+ if (vertically)
+ offset_y = center_y - shell->disp_height / 2 - shell->offset_y;
+
+ gimp_display_shell_scroll (shell, offset_x, offset_y);
+}
+
+/**
+ * gimp_display_shell_scroll_get_scaled_viewport:
+ * @shell:
+ * @x:
+ * @y:
+ * @w:
+ * @h:
+ *
+ * Gets the viewport in screen coordinates, with origin at (0, 0) in
+ * the image.
+ **/
+void
+gimp_display_shell_scroll_get_scaled_viewport (GimpDisplayShell *shell,
+ gint *x,
+ gint *y,
+ gint *w,
+ gint *h)
+{
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ *x = shell->offset_x;
+ *y = shell->offset_y;
+ *w = shell->disp_width;
+ *h = shell->disp_height;
+}
+
+/**
+ * gimp_display_shell_scroll_get_viewport:
+ * @shell:
+ * @x:
+ * @y:
+ * @w:
+ * @h:
+ *
+ * Gets the viewport in image coordinates.
+ **/
+void
+gimp_display_shell_scroll_get_viewport (GimpDisplayShell *shell,
+ gdouble *x,
+ gdouble *y,
+ gdouble *w,
+ gdouble *h)
+{
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ *x = shell->offset_x / shell->scale_x;
+ *y = shell->offset_y / shell->scale_y;
+ *w = shell->disp_width / shell->scale_x;
+ *h = shell->disp_height / shell->scale_y;
+}