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-rw-r--r--app/display/gimpdisplayshell-rotate.c251
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diff --git a/app/display/gimpdisplayshell-rotate.c b/app/display/gimpdisplayshell-rotate.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 <math.h>
+
+#include <gegl.h>
+#include <gtk/gtk.h>
+
+#include "libgimpmath/gimpmath.h"
+
+#include "display-types.h"
+
+#include "gimpdisplay.h"
+#include "gimpdisplayshell.h"
+#include "gimpdisplayshell-expose.h"
+#include "gimpdisplayshell-rotate.h"
+#include "gimpdisplayshell-scale.h"
+#include "gimpdisplayshell-scroll.h"
+#include "gimpdisplayshell-transform.h"
+
+
+#define ANGLE_EPSILON 1e-3
+
+
+/* local function prototypes */
+
+static void gimp_display_shell_save_viewport_center (GimpDisplayShell *shell,
+ gdouble *x,
+ gdouble *y);
+static void gimp_display_shell_restore_viewport_center (GimpDisplayShell *shell,
+ gdouble x,
+ gdouble y);
+
+
+/* public functions */
+
+void
+gimp_display_shell_flip (GimpDisplayShell *shell,
+ gboolean flip_horizontally,
+ gboolean flip_vertically)
+{
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ flip_horizontally = flip_horizontally ? TRUE : FALSE;
+ flip_vertically = flip_vertically ? TRUE : FALSE;
+
+ if (flip_horizontally != shell->flip_horizontally ||
+ flip_vertically != shell->flip_vertically)
+ {
+ gdouble cx, cy;
+
+ /* Maintain the current center of the viewport. */
+ gimp_display_shell_save_viewport_center (shell, &cx, &cy);
+
+ /* freeze the active tool */
+ gimp_display_shell_pause (shell);
+
+ /* Adjust the rotation angle so that the image gets reflected across the
+ * horizontal, and/or vertical, axes in screen space, regardless of the
+ * current rotation.
+ */
+ if (flip_horizontally == shell->flip_horizontally ||
+ flip_vertically == shell->flip_vertically)
+ {
+ if (shell->rotate_angle != 0.0)
+ shell->rotate_angle = 360.0 - shell->rotate_angle;
+ }
+
+ shell->flip_horizontally = flip_horizontally;
+ shell->flip_vertically = flip_vertically;
+
+ gimp_display_shell_rotated (shell);
+
+ gimp_display_shell_restore_viewport_center (shell, cx, cy);
+
+ gimp_display_shell_expose_full (shell);
+
+ /* re-enable the active tool */
+ gimp_display_shell_resume (shell);
+ }
+}
+
+void
+gimp_display_shell_rotate (GimpDisplayShell *shell,
+ gdouble delta)
+{
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ gimp_display_shell_rotate_to (shell, shell->rotate_angle + delta);
+}
+
+void
+gimp_display_shell_rotate_to (GimpDisplayShell *shell,
+ gdouble value)
+{
+ gdouble cx, cy;
+
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ /* Maintain the current center of the viewport. */
+ gimp_display_shell_save_viewport_center (shell, &cx, &cy);
+
+ /* Make sure the angle is within the range [0, 360). */
+ value = fmod (value, 360.0);
+ if (value < 0.0)
+ value += 360.0;
+
+ shell->rotate_angle = value;
+
+ /* freeze the active tool */
+ gimp_display_shell_pause (shell);
+
+ gimp_display_shell_scroll_clamp_and_update (shell);
+
+ gimp_display_shell_rotated (shell);
+
+ gimp_display_shell_restore_viewport_center (shell, cx, cy);
+
+ gimp_display_shell_expose_full (shell);
+
+ /* re-enable the active tool */
+ gimp_display_shell_resume (shell);
+}
+
+void
+gimp_display_shell_rotate_drag (GimpDisplayShell *shell,
+ gdouble last_x,
+ gdouble last_y,
+ gdouble cur_x,
+ gdouble cur_y,
+ gboolean constrain)
+{
+ gdouble pivot_x, pivot_y;
+ gdouble src_x, src_y, src_angle;
+ gdouble dest_x, dest_y, dest_angle;
+ gdouble delta_angle;
+
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ /* Rotate the image around the center of the viewport. */
+ pivot_x = shell->disp_width / 2.0;
+ pivot_y = shell->disp_height / 2.0;
+
+ src_x = last_x - pivot_x;
+ src_y = last_y - pivot_y;
+ src_angle = atan2 (src_y, src_x);
+
+ dest_x = cur_x - pivot_x;
+ dest_y = cur_y - pivot_y;
+ dest_angle = atan2 (dest_y, dest_x);
+
+ delta_angle = dest_angle - src_angle;
+
+ shell->rotate_drag_angle += 180.0 * delta_angle / G_PI;
+
+ gimp_display_shell_rotate_to (shell,
+ constrain ?
+ RINT (shell->rotate_drag_angle / 15.0) * 15.0 :
+ shell->rotate_drag_angle);
+}
+
+void
+gimp_display_shell_rotate_update_transform (GimpDisplayShell *shell)
+{
+ g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+ g_clear_pointer (&shell->rotate_transform, g_free);
+ g_clear_pointer (&shell->rotate_untransform, g_free);
+
+ if (fabs (shell->rotate_angle) < ANGLE_EPSILON ||
+ fabs (360.0 - shell->rotate_angle) < ANGLE_EPSILON)
+ shell->rotate_angle = 0.0;
+
+ if ((shell->rotate_angle != 0.0 ||
+ shell->flip_horizontally ||
+ shell->flip_vertically) &&
+ gimp_display_get_image (shell->display))
+ {
+ gint image_width, image_height;
+ gdouble cx, cy;
+
+ shell->rotate_transform = g_new (cairo_matrix_t, 1);
+ shell->rotate_untransform = g_new (cairo_matrix_t, 1);
+
+ gimp_display_shell_scale_get_image_size (shell,
+ &image_width, &image_height);
+
+ cx = -shell->offset_x + image_width / 2;
+ cy = -shell->offset_y + image_height / 2;
+
+ cairo_matrix_init_translate (shell->rotate_transform, cx, cy);
+
+ if (shell->rotate_angle != 0.0)
+ cairo_matrix_rotate (shell->rotate_transform,
+ shell->rotate_angle / 180.0 * G_PI);
+
+ if (shell->flip_horizontally)
+ cairo_matrix_scale (shell->rotate_transform, -1.0, 1.0);
+
+ if (shell->flip_vertically)
+ cairo_matrix_scale (shell->rotate_transform, 1.0, -1.0);
+
+ cairo_matrix_translate (shell->rotate_transform, -cx, -cy);
+
+ *shell->rotate_untransform = *shell->rotate_transform;
+ cairo_matrix_invert (shell->rotate_untransform);
+ }
+}
+
+
+/* private functions */
+
+static void
+gimp_display_shell_save_viewport_center (GimpDisplayShell *shell,
+ gdouble *x,
+ gdouble *y)
+{
+ gimp_display_shell_unrotate_xy_f (shell,
+ shell->disp_width / 2,
+ shell->disp_height / 2,
+ x, y);
+}
+
+static void
+gimp_display_shell_restore_viewport_center (GimpDisplayShell *shell,
+ gdouble x,
+ gdouble y)
+{
+ gimp_display_shell_rotate_xy_f (shell, x, y, &x, &y);
+
+ x += shell->offset_x - shell->disp_width / 2;
+ y += shell->offset_y - shell->disp_height / 2;
+
+ gimp_display_shell_scroll_set_offset (shell, RINT (x), RINT (y));
+}
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