New Magic tool: "Tile Zoom"

docs/CHANGES.txt

@@ -85,6 +85,11 @@ http://www.tuxpaint.org/
     * Don't play 'bubble' paint sound when color picker or selector
       (or new mixer) are aborted (via their "Back" buttons or [Esc] key).
 
+  * New Magic Tools:
+    ----------------
+    * "Tile Zoom"; like the regular "Zoom", but tiles the results when
+      you scale down (similar to "Panels", but with non-integer scaling).
+
   * Localization Updates:
     ---------------------
     * Albanian translation

magic/src/perspective.c

@@ -2,13 +2,14 @@
   perspective.c
 
   perspective, stretches the plane of the image.
-  zoom, zooms in and out the image.
+  zoom & tile zoom, zooms in and out the image.
+  panels, turns the images into a 2x2 grid.
 
   Tux Paint - A simple drawing program for children.
 
   Credits: Andrew Corcoran <akanewbie@gmail.com>
 
-  Copyright (c) 2002-2021 by Bill Kendrick and others; see AUTHORS.txt
+  Copyright (c) 2002-2022 by Bill Kendrick and others; see AUTHORS.txt
   bill@newbreedsoftware.com
   http://www.tuxpaint.org/
 
@@ -27,7 +28,7 @@
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   (See COPYING.txt)
 
-  Last updated: September 20, 2021
+  Last updated: January 30, 2022
   $Id$
 */
 
@@ -116,6 +117,7 @@ enum
 {
   TOOL_PERSPECTIVE,
   TOOL_PANELS,
+  TOOL_TILEZOOM,
   TOOL_ZOOM,
   perspective_NUM_TOOLS
 };
@@ -144,12 +146,14 @@ const char *perspective_snd_filenames[perspective_NUM_TOOLS + 1] = {
 const char *perspective_icon_filenames[perspective_NUM_TOOLS] = {
   "perspective.png",
   "panels.png",
+  "tilezoom.png",
   "zoom.png",
 };
 
 const char *perspective_names[perspective_NUM_TOOLS] = {
   gettext_noop("Perspective"),
   gettext_noop("Panels"),
+  gettext_noop("Tile Zoom"),
   gettext_noop("Zoom"),
 };
 
@@ -159,6 +163,8 @@ const char *perspective_descs[perspective_NUM_TOOLS] = {
   gettext_noop("Click to turn your picture into 2-by-2 panels."),
 
   gettext_noop("Click and drag up to zoom in or drag down to zoom out the picture."),
+
+  gettext_noop("Click and drag up to zoom in or drag down to zoom out the picture."),
 };
 
 Uint32 perspective_api_version(void)
@@ -282,14 +288,18 @@ void perspective_drag(magic_api * api, int which, SDL_Surface * canvas,
       }
       break;
     case TOOL_ZOOM:
+    case TOOL_TILEZOOM:
       {
         int x_distance, y_distance;
 
-        update_rect->x = update_rect->y = 0;
+        if (which == TOOL_ZOOM)
-        update_rect->w = canvas->w;
+          {
-        update_rect->h = canvas->h;
+            update_rect->x = update_rect->y = 0;
+            update_rect->w = canvas->w;
+            update_rect->h = canvas->h;
     
-        SDL_FillRect(canvas, update_rect, SDL_MapRGB(canvas->format, perspective_r, perspective_g, perspective_b));
+            SDL_FillRect(canvas, update_rect, SDL_MapRGB(canvas->format, perspective_r, perspective_g, perspective_b));
+          }
 
         new_h = max(1, old_h + click_y - y);
         new_w = canvas->w * new_h / canvas->h;
@@ -361,6 +371,7 @@ void perspective_click(magic_api * api, int which, int mode ATTRIBUTE_UNUSED,
       }
       break;
     case TOOL_ZOOM:
+    case TOOL_TILEZOOM:
       {
         click_x = x;
         click_y = y;
@@ -433,6 +444,7 @@ void perspective_release(magic_api * api, int which,
       break;
 
     case TOOL_ZOOM:
+    case TOOL_TILEZOOM:
       {
         SDL_Surface *aux_surf;
         SDL_Surface *scaled_surf;
@@ -441,17 +453,35 @@ void perspective_release(magic_api * api, int which,
         update_rect->w = canvas->w;
         update_rect->h = canvas->h;
 
-        SDL_FillRect(canvas, update_rect, SDL_MapRGB(canvas->format, perspective_r, perspective_g, perspective_b));
+        if (which == TOOL_ZOOM)
+          SDL_FillRect(canvas, update_rect, SDL_MapRGB(canvas->format, perspective_r, perspective_g, perspective_b));
 
 
         if (new_h < canvas->h)
           {
+            int xx, yy, x_span, y_span;
+
             scaled_surf = api->scale(canvas_back, new_w, new_h, 0);
-            update_rect->x = (canvas->w - new_w) / 2;
+
-            update_rect->y = (canvas->h - new_h) / 2;
+            if (which == TOOL_TILEZOOM && (new_w < canvas->w || new_h < canvas->h))
-            update_rect->w = new_w;
+              {
-            update_rect->h = new_h;
+                x_span = ceil(canvas->w / new_w);
-            SDL_BlitSurface(scaled_surf, NULL, canvas, update_rect);
+                y_span = ceil(canvas->h / new_h);
+              }
+            else
+              x_span = y_span = 0;
+
+            for (yy = -y_span; yy <= y_span; yy++)
+              {
+                for (xx = -x_span; xx <= x_span; xx++)
+                  {
+                    update_rect->x = ((canvas->w - new_w) / 2) + (new_w * xx);
+                    update_rect->y = ((canvas->h - new_h) / 2) + (new_h * yy);
+                    update_rect->w = new_w;
+                    update_rect->h = new_h;
+                    SDL_BlitSurface(scaled_surf, NULL, canvas, update_rect);
+                  }
+              }
           }
         else
           {
@@ -487,7 +517,7 @@ void perspective_release(magic_api * api, int which,
     }
 }
 
-void perspective_preview(magic_api * api, int which ATTRIBUTE_UNUSED,
+void perspective_preview(magic_api * api, int which,
                          SDL_Surface * canvas, SDL_Surface * last ATTRIBUTE_UNUSED,
                          int x ATTRIBUTE_UNUSED, int y ATTRIBUTE_UNUSED, SDL_Rect * update_rect, float step)
 {
@@ -501,7 +531,10 @@ void perspective_preview(magic_api * api, int which ATTRIBUTE_UNUSED,
   update_rect->w = canvas->w;
   update_rect->h = canvas->h;
 
-  SDL_FillRect(canvas, update_rect, SDL_MapRGB(canvas->format, perspective_r, perspective_g, perspective_b));
+  if (which == TOOL_ZOOM)
+    SDL_FillRect(canvas, update_rect, SDL_MapRGB(canvas->format, perspective_r, perspective_g, perspective_b));
+  else if (which == TOOL_TILEZOOM)
+    SDL_FillRect(canvas, update_rect, SDL_MapRGB(canvas->format, 128, 128, 128));
 
   ox_distance = otop_right_x - otop_left_x;
   oy_distance = obottom_left_y - otop_left_y;
@@ -537,6 +570,35 @@ void perspective_preview(magic_api * api, int which ATTRIBUTE_UNUSED,
           api->putpixel(canvas, ax + dx - center_ofset_x, ay + dy - center_ofset_y, api->getpixel(canvas_back, i, j));
         }
     }
+
+  if (which == TOOL_TILEZOOM && new_w >= 2 && new_h >= 2)
+    {
+      int xx, yy, x_span, y_span;
+      SDL_Rect src_rect, dest_rect;
+
+      x_span = ceil(canvas->w / new_w);
+      y_span = ceil(canvas->h / new_h);
+
+      src_rect.x = -center_ofset_x;
+      src_rect.y = -center_ofset_y;
+      src_rect.w = new_w;
+      src_rect.h = new_h;
+
+      for (yy = -y_span; yy <= y_span; yy++)
+        {
+          for (xx = -x_span; xx <= x_span; xx++)
+            {
+              if (xx != 0 || yy != 0)
+                {
+                  dest_rect.x = ((canvas->w - new_w) / 2) + (new_w * xx);
+                  dest_rect.y = ((canvas->h - new_h) / 2) + (new_h * yy);
+                  dest_rect.w = new_w;
+                  dest_rect.h = new_h;
+                  SDL_BlitSurface(canvas, &src_rect, canvas, &dest_rect);
+                }
+            }
+        }
+    }
 }
 
 void perspective_shutdown(magic_api * api ATTRIBUTE_UNUSED)
@@ -564,7 +626,7 @@ void perspective_set_color(magic_api * api ATTRIBUTE_UNUSED, Uint8 r, Uint8 g, U
 // Use colors:
 int perspective_requires_colors(magic_api * api ATTRIBUTE_UNUSED, int which)
 {
-  if (which == TOOL_PANELS)
+  if (which == TOOL_PANELS || which == TOOL_TILEZOOM)
     return 0;
   return 1;
 }