[gimp/blend-tool-fun: 137/163] app: add gimp_display_shell_scale_to_rectangle()

[Michael Henning <mhenning src gnome org>]

commit af32114dd9ad755eb69679edf45284e70688c474
Author: Michael Natterer <mitch gimp org>
Date:   Sun Oct 18 14:59:30 2015 +0200

    app: add gimp_display_shell_scale_to_rectangle()
    
    and move the magnify tool's rectangle zoom logic to the new function.

 app/display/gimpdisplayshell-scale.c |  127 ++++++++++++++++++++++++++++++++++
 app/display/gimpdisplayshell-scale.h |    7 ++
 app/tools/gimpmagnifytool.c          |  116 +++----------------------------
 3 files changed, 143 insertions(+), 107 deletions(-)
---
diff --git a/app/display/gimpdisplayshell-scale.c b/app/display/gimpdisplayshell-scale.c
index 2a0d767..506bfe8 100644
--- a/app/display/gimpdisplayshell-scale.c
+++ b/app/display/gimpdisplayshell-scale.c
@@ -497,6 +497,133 @@ gimp_display_shell_scale (GimpDisplayShell *shell,
 }
 
 /**
+ * gimp_display_shell_scale_to_rectangle:
+ * @shell:         the #GimpDisplayShell
+ * @zoom_type:     whether to zoom in or out
+ * @x:             retangle's x in image coordinates
+ * @y:             retangle's y in image coordinates
+ * @width:         retangle's width in image coordinates
+ * @height:        retangle's height in image coordinates
+ * @resize_window: whether the display window should be resized
+ *
+ * Scales and scrolls to a specific image rectangle
+ **/
+void
+gimp_display_shell_scale_to_rectangle (GimpDisplayShell *shell,
+                                       GimpZoomType      zoom_type,
+                                       gdouble           x,
+                                       gdouble           y,
+                                       gdouble           width,
+                                       gdouble           height,
+                                       gboolean          resize_window)
+{
+  gdouble current_scale;
+  gdouble new_scale;
+  gdouble display_width;
+  gdouble display_height;
+  gdouble factor = 1.0;
+
+  g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
+
+  width  = MAX (1.0, width);
+  height = MAX (1.0, height);
+
+  current_scale = gimp_zoom_model_get_factor (shell->zoom);
+
+  display_width  = FUNSCALEX (shell, shell->disp_width);
+  display_height = FUNSCALEY (shell, shell->disp_height);
+
+  switch (zoom_type)
+    {
+    case GIMP_ZOOM_IN:
+      factor = MIN ((display_width  / width),
+                    (display_height / height));
+      break;
+
+    case GIMP_ZOOM_OUT:
+      factor = MAX ((width  / display_width),
+                    (height / display_height));
+      break;
+
+    default:
+      g_return_if_reached ();
+      break;
+    }
+
+  new_scale = current_scale * factor;
+
+  if (new_scale != current_scale)
+    {
+      GimpImage *image    = gimp_display_get_image (shell->display);
+      gint       offset_x = 0;
+      gint       offset_y = 0;
+      gdouble    xres;
+      gdouble    yres;
+      gdouble    screen_xres;
+      gdouble    screen_yres;
+
+      gimp_image_get_resolution (image, &xres, &yres);
+      gimp_display_shell_get_screen_resolution (shell,
+                                                &screen_xres, &screen_yres);
+
+      switch (zoom_type)
+        {
+        case GIMP_ZOOM_IN:
+          /*  move the center of the rectangle to the center of the
+           *  viewport:
+           *
+           *  new_offset = center of rectangle in new scale screen coords
+           *               including offset
+           *               -
+           *               center of viewport in screen coords without
+           *               offset
+           */
+          offset_x = RINT (new_scale * (x + width / 2.0) *
+                           screen_xres / xres -
+                           (shell->disp_width / 2.0));
+
+          offset_y = RINT (new_scale * (y + height / 2.0) *
+                           screen_yres / yres -
+                           (shell->disp_height / 2.0));
+          break;
+
+        case GIMP_ZOOM_OUT:
+          /*  move the center of the viewport to the center of the
+           *  rectangle:
+           *
+           *  new_offset = center of viewport in new scale screen coords
+           *               including offset
+           *               -
+           *               center of rectangle in screen coords without
+           *               offset
+           */
+          offset_x = RINT (new_scale * UNSCALEX (shell,
+                                                 shell->offset_x +
+                                                 shell->disp_width / 2.0) *
+                           screen_xres / xres -
+                           (SCALEX (shell, x + width / 2.0) -
+                            shell->offset_x));
+
+          offset_y = RINT (new_scale * UNSCALEY (shell,
+                                                 shell->offset_y +
+                                                 shell->disp_height / 2.0) *
+                           screen_yres / yres -
+                           (SCALEY (shell, y + height / 2.0) -
+                            shell->offset_y));
+          break;
+
+        default:
+          break;
+        }
+
+      gimp_display_shell_scale_by_values (shell,
+                                          new_scale,
+                                          offset_x, offset_y,
+                                          resize_window);
+    }
+}
+
+/**
  * gimp_display_shell_scale_fit_in:
  * @shell: the #GimpDisplayShell
  *
diff --git a/app/display/gimpdisplayshell-scale.h b/app/display/gimpdisplayshell-scale.h
index 6458428..f3d7532 100644
--- a/app/display/gimpdisplayshell-scale.h
+++ b/app/display/gimpdisplayshell-scale.h
@@ -43,6 +43,13 @@ void     gimp_display_shell_scale                          (GimpDisplayShell *sh
                                                             GimpZoomType      zoom_type,
                                                             gdouble           scale,
                                                             GimpZoomFocus     zoom_focus);
+void     gimp_display_shell_scale_to_rectangle             (GimpDisplayShell *shell,
+                                                            GimpZoomType      zoom_type,
+                                                            gdouble           x,
+                                                            gdouble           y,
+                                                            gdouble           width,
+                                                            gdouble           height,
+                                                            gboolean          resize_window);
 void     gimp_display_shell_scale_fit_in                   (GimpDisplayShell *shell);
 gboolean gimp_display_shell_scale_image_is_within_viewport (GimpDisplayShell *shell,
                                                             gboolean         *horizontally,
diff --git a/app/tools/gimpmagnifytool.c b/app/tools/gimpmagnifytool.c
index 3972232..48b3dbb 100644
--- a/app/tools/gimpmagnifytool.c
+++ b/app/tools/gimpmagnifytool.c
@@ -183,116 +183,18 @@ gimp_magnify_tool_button_release (GimpTool              *tool,
 
     case GIMP_BUTTON_RELEASE_NORMAL:
       {
-        gdouble x1, y1, x2, y2;
+        gdouble x, y;
         gdouble width, height;
-        gdouble current_scale;
-        gdouble new_scale;
-        gdouble display_width;
-        gdouble display_height;
-        gdouble factor = 1.0;
-
-        x1     = (magnify->w < 0) ?  magnify->x + magnify->w : magnify->x;
-        y1     = (magnify->h < 0) ?  magnify->y + magnify->h : magnify->y;
+
+        x      = (magnify->w < 0) ?  magnify->x + magnify->w : magnify->x;
+        y      = (magnify->h < 0) ?  magnify->y + magnify->h : magnify->y;
         width  = (magnify->w < 0) ? -magnify->w : magnify->w;
         height = (magnify->h < 0) ? -magnify->h : magnify->h;
-        x2     = x1 + width;
-        y2     = y1 + height;
-
-        width  = MAX (1.0, width);
-        height = MAX (1.0, height);
-
-        current_scale = gimp_zoom_model_get_factor (shell->zoom);
-
-        display_width  = FUNSCALEX (shell, shell->disp_width);
-        display_height = FUNSCALEY (shell, shell->disp_height);
-
-        switch (options->zoom_type)
-          {
-          case GIMP_ZOOM_IN:
-            factor = MIN ((display_width  / width),
-                          (display_height / height));
-            break;
-
-          case GIMP_ZOOM_OUT:
-            factor = MAX ((width  / display_width),
-                          (height / display_height));
-            break;
-
-          default:
-            break;
-          }
-
-        new_scale = current_scale * factor;
-
-        if (new_scale != current_scale)
-          {
-            gint    offset_x = 0;
-            gint    offset_y = 0;
-            gdouble xres;
-            gdouble yres;
-            gdouble screen_xres;
-            gdouble screen_yres;
-
-            gimp_image_get_resolution (gimp_display_get_image (display),
-                                       &xres, &yres);
-            gimp_display_shell_get_screen_resolution (shell,
-                                                      &screen_xres, &screen_yres);
-
-            switch (options->zoom_type)
-              {
-              case GIMP_ZOOM_IN:
-                /*  move the center of the rectangle to the center of the
-                 *  viewport:
-                 *
-                 *  new_offset = center of rectangle in new scale screen coords
-                 *               including offset
-                 *               -
-                 *               center of viewport in screen coords without
-                 *               offset
-                 */
-                offset_x = RINT (new_scale * ((x1 + x2) / 2.0) *
-                                 screen_xres / xres -
-                                 (shell->disp_width / 2.0));
-
-                offset_y = RINT (new_scale * ((y1 + y2) / 2.0) *
-                                 screen_yres / yres -
-                                 (shell->disp_height / 2.0));
-                break;
-
-              case GIMP_ZOOM_OUT:
-                /*  move the center of the viewport to the center of the
-                 *  rectangle:
-                 *
-                 *  new_offset = center of viewport in new scale screen coords
-                 *               including offset
-                 *               -
-                 *               center of rectangle in screen coords without
-                 *               offset
-                 */
-                offset_x = RINT (new_scale * UNSCALEX (shell,
-                                                       shell->offset_x +
-                                                       shell->disp_width / 2.0) *
-                                 screen_xres / xres -
-                                 (SCALEX (shell, (x1 + x2) / 2.0) -
-                                  shell->offset_x));
-
-                offset_y = RINT (new_scale * UNSCALEY (shell,
-                                                       shell->offset_y +
-                                                       shell->disp_height / 2.0) *
-                                 screen_yres / yres -
-                                 (SCALEY (shell, (y1 + y2) / 2.0) -
-                                  shell->offset_y));
-                break;
-
-              default:
-                break;
-              }
-
-            gimp_display_shell_scale_by_values (shell,
-                                                new_scale,
-                                                offset_x, offset_y,
-                                                options->auto_resize);
-          }
+
+        gimp_display_shell_scale_to_rectangle (shell,
+                                               options->zoom_type,
+                                               x, y, width, height,
+                                               options->auto_resize);
       }
       break;