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-rw-r--r--app/core/gimppickable-auto-shrink.c312
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diff --git a/app/core/gimppickable-auto-shrink.c b/app/core/gimppickable-auto-shrink.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 <string.h>
+
+#include <gdk-pixbuf/gdk-pixbuf.h>
+#include <gegl.h>
+
+#include "core-types.h"
+
+#include "gimp.h"
+#include "gimpimage.h"
+#include "gimppickable.h"
+#include "gimppickable-auto-shrink.h"
+
+
+typedef enum
+{
+ AUTO_SHRINK_NOTHING = 0,
+ AUTO_SHRINK_ALPHA = 1,
+ AUTO_SHRINK_COLOR = 2
+} AutoShrinkType;
+
+
+typedef gboolean (* ColorsEqualFunc) (guchar *col1,
+ guchar *col2);
+
+
+/* local function prototypes */
+
+static AutoShrinkType gimp_pickable_guess_bgcolor (GimpPickable *pickable,
+ guchar *color,
+ gint x1,
+ gint x2,
+ gint y1,
+ gint y2);
+static gboolean gimp_pickable_colors_equal (guchar *col1,
+ guchar *col2);
+static gboolean gimp_pickable_colors_alpha (guchar *col1,
+ guchar *col2);
+
+
+/* public functions */
+
+GimpAutoShrink
+gimp_pickable_auto_shrink (GimpPickable *pickable,
+ gint start_x,
+ gint start_y,
+ gint start_width,
+ gint start_height,
+ gint *shrunk_x,
+ gint *shrunk_y,
+ gint *shrunk_width,
+ gint *shrunk_height)
+{
+ GeglBuffer *buffer;
+ GeglRectangle rect;
+ ColorsEqualFunc colors_equal_func;
+ guchar bgcolor[MAX_CHANNELS] = { 0, 0, 0, 0 };
+ guchar *buf = NULL;
+ gint x1, y1, x2, y2;
+ gint width, height;
+ const Babl *format;
+ gint x, y, abort;
+ GimpAutoShrink retval = GIMP_AUTO_SHRINK_UNSHRINKABLE;
+
+ g_return_val_if_fail (GIMP_IS_PICKABLE (pickable), FALSE);
+ g_return_val_if_fail (shrunk_x != NULL, FALSE);
+ g_return_val_if_fail (shrunk_y != NULL, FALSE);
+ g_return_val_if_fail (shrunk_width != NULL, FALSE);
+ g_return_val_if_fail (shrunk_height != NULL, FALSE);
+
+ gimp_set_busy (gimp_pickable_get_image (pickable)->gimp);
+
+ /* You should always keep in mind that x2 and y2 are the NOT the
+ * coordinates of the bottomright corner of the area to be
+ * cropped. They point at the pixel located one to the right and one
+ * to the bottom.
+ */
+
+ gimp_pickable_flush (pickable);
+
+ buffer = gimp_pickable_get_buffer (pickable);
+
+ x1 = MAX (start_x, 0);
+ y1 = MAX (start_y, 0);
+ x2 = MIN (start_x + start_width, gegl_buffer_get_width (buffer));
+ y2 = MIN (start_y + start_height, gegl_buffer_get_height (buffer));
+
+ /* By default, return the start values */
+ *shrunk_x = x1;
+ *shrunk_y = y1;
+ *shrunk_width = x2 - x1;
+ *shrunk_height = y2 - y1;
+
+ format = babl_format ("R'G'B'A u8");
+
+ switch (gimp_pickable_guess_bgcolor (pickable, bgcolor,
+ x1, x2 - 1, y1, y2 - 1))
+ {
+ case AUTO_SHRINK_ALPHA:
+ colors_equal_func = gimp_pickable_colors_alpha;
+ break;
+ case AUTO_SHRINK_COLOR:
+ colors_equal_func = gimp_pickable_colors_equal;
+ break;
+ default:
+ goto FINISH;
+ break;
+ }
+
+ width = x2 - x1;
+ height = y2 - y1;
+
+ /* The following could be optimized further by processing
+ * the smaller side first instead of defaulting to width --Sven
+ */
+
+ buf = g_malloc (MAX (width, height) * 4);
+
+ /* Check how many of the top lines are uniform/transparent. */
+ rect.x = x1;
+ rect.y = 0;
+ rect.width = width;
+ rect.height = 1;
+
+ abort = FALSE;
+ for (y = y1; y < y2 && !abort; y++)
+ {
+ rect.y = y;
+ gegl_buffer_get (buffer, &rect, 1.0, format, buf,
+ GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);
+ for (x = 0; x < width && !abort; x++)
+ abort = ! colors_equal_func (bgcolor, buf + x * 4);
+ }
+ if (y == y2 && !abort)
+ {
+ retval = GIMP_AUTO_SHRINK_EMPTY;
+ goto FINISH;
+ }
+ y1 = y - 1;
+
+ /* Check how many of the bottom lines are uniform/transparent. */
+ rect.x = x1;
+ rect.y = 0;
+ rect.width = width;
+ rect.height = 1;
+
+ abort = FALSE;
+ for (y = y2; y > y1 && !abort; y--)
+ {
+ rect.y = y - 1;
+ gegl_buffer_get (buffer, &rect, 1.0, format, buf,
+ GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);
+ for (x = 0; x < width && !abort; x++)
+ abort = ! colors_equal_func (bgcolor, buf + x * 4);
+ }
+ y2 = y + 1;
+
+ /* compute a new height for the next operations */
+ height = y2 - y1;
+
+ /* Check how many of the left lines are uniform/transparent. */
+ rect.x = 0;
+ rect.y = y1;
+ rect.width = 1;
+ rect.height = height;
+
+ abort = FALSE;
+ for (x = x1; x < x2 && !abort; x++)
+ {
+ rect.x = x;
+ gegl_buffer_get (buffer, &rect, 1.0, format, buf,
+ GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);
+ for (y = 0; y < height && !abort; y++)
+ abort = ! colors_equal_func (bgcolor, buf + y * 4);
+ }
+ x1 = x - 1;
+
+ /* Check how many of the right lines are uniform/transparent. */
+ rect.x = 0;
+ rect.y = y1;
+ rect.width = 1;
+ rect.height = height;
+
+ abort = FALSE;
+ for (x = x2; x > x1 && !abort; x--)
+ {
+ rect.x = x - 1;
+ gegl_buffer_get (buffer, &rect, 1.0, format, buf,
+ GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);
+ for (y = 0; y < height && !abort; y++)
+ abort = ! colors_equal_func (bgcolor, buf + y * 4);
+ }
+ x2 = x + 1;
+
+ if (x1 != start_x ||
+ y1 != start_y ||
+ x2 - x1 != start_width ||
+ y2 - y1 != start_height)
+ {
+ *shrunk_x = x1;
+ *shrunk_y = y1;
+ *shrunk_width = x2 - x1;
+ *shrunk_height = y2 - y1;
+
+ retval = GIMP_AUTO_SHRINK_SHRINK;
+ }
+
+ FINISH:
+
+ g_free (buf);
+ gimp_unset_busy (gimp_pickable_get_image (pickable)->gimp);
+
+ return retval;
+}
+
+
+/* private functions */
+
+static AutoShrinkType
+gimp_pickable_guess_bgcolor (GimpPickable *pickable,
+ guchar *color,
+ gint x1,
+ gint x2,
+ gint y1,
+ gint y2)
+{
+ const Babl *format = babl_format ("R'G'B'A u8");
+ guchar tl[4];
+ guchar tr[4];
+ guchar bl[4];
+ guchar br[4];
+ gint i;
+
+ for (i = 0; i < 4; i++)
+ color[i] = 0;
+
+ /* First check if there's transparency to crop. If not, guess the
+ * background-color to see if at least 2 corners are equal.
+ */
+
+ if (! gimp_pickable_get_pixel_at (pickable, x1, y1, format, tl) ||
+ ! gimp_pickable_get_pixel_at (pickable, x1, y2, format, tr) ||
+ ! gimp_pickable_get_pixel_at (pickable, x2, y1, format, bl) ||
+ ! gimp_pickable_get_pixel_at (pickable, x2, y2, format, br))
+ {
+ return AUTO_SHRINK_NOTHING;
+ }
+
+ if ((tl[ALPHA] == 0 && tr[ALPHA] == 0) ||
+ (tl[ALPHA] == 0 && bl[ALPHA] == 0) ||
+ (tr[ALPHA] == 0 && br[ALPHA] == 0) ||
+ (bl[ALPHA] == 0 && br[ALPHA] == 0))
+ {
+ return AUTO_SHRINK_ALPHA;
+ }
+
+ if (gimp_pickable_colors_equal (tl, tr) ||
+ gimp_pickable_colors_equal (tl, bl))
+ {
+ memcpy (color, tl, 4);
+ return AUTO_SHRINK_COLOR;
+ }
+
+ if (gimp_pickable_colors_equal (br, bl) ||
+ gimp_pickable_colors_equal (br, tr))
+ {
+ memcpy (color, br, 4);
+ return AUTO_SHRINK_COLOR;
+ }
+
+ return AUTO_SHRINK_NOTHING;
+}
+
+static gboolean
+gimp_pickable_colors_equal (guchar *col1,
+ guchar *col2)
+{
+ gint b;
+
+ for (b = 0; b < 4; b++)
+ {
+ if (col1[b] != col2[b])
+ return FALSE;
+ }
+
+ return TRUE;
+}
+
+static gboolean
+gimp_pickable_colors_alpha (guchar *dummy,
+ guchar *col)
+{
+ return (col[ALPHA] == 0);
+}
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