WIP "Rotate" magic tool

Rotates the canvas

docs/CHANGES.txt

@@ -6,7 +6,7 @@ Copyright (c) 2002-2024
 Various contributors (see below, and AUTHORS.txt)
 https://tuxpaint.org/
 
-2024.September.23 (0.9.34)
+2024.September.24 (0.9.34)
   * New Magic Tools:
     ----------------
     * "Comic Dots", draws repeating dots (using a multiply blend)
@@ -17,6 +17,12 @@ https://tuxpaint.org/
         <https://freesound.org/people/humanoide9000/>
       + Closes https://sourceforge.net/p/tuxpaint/feature-requests/257/
 
+    * "Rotate", rotate's the entire image on the canvas.
+      + Bill Kendrick <bill@newbreedsoftware.com>
+      + TODO Sound effect
+      + TODO Icon
+      + TODO Documentation
+
     * "Fractal", a set of freehand drawing tools that
       recursively draw variations of the strokes
       + Bill Kendrick <bill@newbreedsoftware.com>
@@ -1696,7 +1702,7 @@ https://tuxpaint.org/
       + Note: This adds a dependency on "SDL_gfx" library
         (Homepage: https://www.ferzkopp.net/wordpress/2016/01/02/sdl_gfx-sdl2_gfx/
         SourceForge project page: https://sourceforge.net/projects/sdlgfx/)
-        as this feature use it's "rotozoomSurface()" and "SDL_gfxBlitRGBA()".
+        as this feature use its "rotozoomSurface()" and "SDL_gfxBlitRGBA()".
       (Closes https://sourceforge.net/p/tuxpaint/feature-requests/122/)
 
     * Replaced the "arrow_compass_points" brush with a single

magic/src/rotate.c

@@ -0,0 +1,294 @@
+/*
+  rotate.c
+
+  Rotates the image on the canvas.
+
+  Tux Paint - A simple drawing program for children.
+
+  Copyright (c) 2024 by Bill Kendrick
+
+  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 2 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, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  (See COPYING.txt)
+
+  Last updated: September 24, 2024
+*/
+
+#include <stdio.h>
+#include <string.h>
+#include "tp_magic_api.h"
+#include "SDL_image.h"
+#include "SDL_mixer.h"
+#include "SDL2_rotozoom.h"
+
+static Mix_Chunk *rotate_snd;
+SDL_Surface * rotate_snapshot = NULL;
+Uint32 rotate_color;
+float rotate_last_angle = 0.0;
+int rotate_clicked_since_switchin = 0;
+
+Uint32 rotate_api_version(void);
+int rotate_init(magic_api * api, Uint8 disabled_features, Uint8 complexity_level);
+int rotate_get_tool_count(magic_api * api);
+SDL_Surface *rotate_get_icon(magic_api * api, int which);
+char *rotate_get_name(magic_api * api, int which);
+int rotate_get_group(magic_api * api, int which);
+int rotate_get_order(int which);
+char *rotate_get_description(magic_api * api, int which, int mode);
+
+void rotate_drag(magic_api * api, int which, SDL_Surface * canvas,
+              SDL_Surface * last, int ox, int oy, int x, int y, SDL_Rect * update_rect);
+
+void rotate_click(magic_api * api, int which, int mode,
+               SDL_Surface * canvas, SDL_Surface * last, int x, int y, SDL_Rect * update_rect);
+
+void rotate_release(magic_api * api, int which,
+                 SDL_Surface * canvas, SDL_Surface * last, int x, int y, SDL_Rect * update_rect);
+
+void rotate_shutdown(magic_api * api);
+void rotate_set_color(magic_api * api, int which, SDL_Surface * canvas,
+                   SDL_Surface * last, Uint8 r, Uint8 g, Uint8 b, SDL_Rect * update_rect);
+int rotate_requires_colors(magic_api * api, int which);
+void rotate_switchin(magic_api * api, int which, int mode, SDL_Surface * canvas);
+void rotate_switchout(magic_api * api, int which, int mode, SDL_Surface * canvas);
+int rotate_modes(magic_api * api, int which);
+Uint8 rotate_accepted_sizes(magic_api * api, int which, int mode);
+Uint8 rotate_default_size(magic_api * api, int which, int mode);
+void rotate_set_size(magic_api * api, int which, int mode, SDL_Surface * canvas, SDL_Surface * last, Uint8 size,
+                  SDL_Rect * update_rect);
+float do_rotate(SDL_Surface * canvas, int x, int y, int smoothing_flag);
+
+
+Uint32 rotate_api_version(void)
+{
+  return (TP_MAGIC_API_VERSION);
+}
+
+int rotate_init(magic_api * api, Uint8 disabled_features ATTRIBUTE_UNUSED, Uint8 complexity_level ATTRIBUTE_UNUSED)
+{
+  char fname[1024];
+
+  snprintf(fname, sizeof(fname), "%ssounds/magic/xor.ogg", api->data_directory); // FIXME
+  rotate_snd = Mix_LoadWAV(fname);
+
+  return (1);
+}
+
+int rotate_get_tool_count(magic_api * api ATTRIBUTE_UNUSED)
+{
+  return (1);
+}
+
+SDL_Surface *rotate_get_icon(magic_api * api, int which ATTRIBUTE_UNUSED)
+{
+  char fname[1024];
+
+  snprintf(fname, sizeof(fname), "%simages/magic/xor.png", api->data_directory); // FIXME
+
+  return (IMG_Load(fname));
+}
+
+char *rotate_get_name(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED)
+{
+  return (strdup(gettext_noop("Rotate")));
+}
+
+int rotate_get_group(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED)
+{
+  return MAGIC_TYPE_PICTURE_WARPS;
+}
+
+int rotate_get_order(int which ATTRIBUTE_UNUSED)
+{
+  return 900;
+}
+
+char *rotate_get_description(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED, int mode ATTRIBUTE_UNUSED)
+{
+  return (strdup(gettext_noop("Click and drag to rotate your drawing.")));
+}
+
+float do_rotate(SDL_Surface * canvas, int x, int y, int smoothing_flag)
+{
+  SDL_Surface * new_surf;
+  float angle_rad;
+  SDL_Rect dest;
+
+  if (rotate_snapshot == NULL)
+    return 0.0; /* abort! */
+
+  /* Render a rotated version of the snapshot */
+  /* ---------------------------------------- */
+  /* Calculate angle based on X/Y click vs. center of canvas */
+  angle_rad = -atan2(y - (canvas->h / 2), x - (canvas->w / 2));
+  /* Add previous angle, so they stack up
+     (allows you to click a spot, and while rotating it remains
+     under the pointer; versus always re-rotating) */
+  angle_rad += rotate_last_angle;
+  new_surf = rotozoomSurface(rotate_snapshot, (angle_rad * 180.0 / M_PI), 1.0 /* no zoom */, smoothing_flag);
+
+  /* Draw background color on canvas */
+  /* ------------------------------- */
+  SDL_FillRect(canvas, NULL, rotate_color);
+
+  /* Place rotated version in the center of the live canvas */
+  /* ------------------------------------------------------ */
+  dest.x = (canvas->w - new_surf->w) / 2;
+  dest.y = (canvas->h - new_surf->h) / 2;
+  dest.w = new_surf->w;
+  dest.h = new_surf->h;
+  SDL_BlitSurface(new_surf, NULL, canvas, &dest);
+
+  /* Return the angle we ended up at */
+  return angle_rad;
+}
+
+void rotate_drag(magic_api * api, int which ATTRIBUTE_UNUSED, SDL_Surface * canvas,
+              SDL_Surface * last ATTRIBUTE_UNUSED, int ox ATTRIBUTE_UNUSED, int oy ATTRIBUTE_UNUSED,
+              int x, int y, SDL_Rect * update_rect)
+{
+  /* Rotate interactively based on the X/Y position of the mouse */
+  do_rotate(canvas, x, y, SMOOTHING_OFF);
+
+  update_rect->x = 0;
+  update_rect->y = 0;
+  update_rect->w = canvas->w;
+  update_rect->h = canvas->h;
+
+  api->playsound(rotate_snd, 128, 255);
+}
+
+void rotate_click(magic_api * api, int which, int mode ATTRIBUTE_UNUSED,
+               SDL_Surface * canvas, SDL_Surface * last, int x, int y, SDL_Rect * update_rect)
+{
+  /* Calculate the starting angle as the OPPOSITE of
+   * where you clicked (so that `rotate_drag()` ends up
+   * rotating 0 radians), and stack it onto the current angle */
+  rotate_last_angle += atan2(y - (canvas->h / 2), x - (canvas->w / 2));
+
+  /* Record the fact that we've clicked at least once since
+   * switching [back] to thsi tool */
+  rotate_clicked_since_switchin = 1;
+
+  /* Call the drag function to do the work
+   * (it will add the click positions angle, making it a net
+   * 0-radian rotation _this time_) */
+  rotate_drag(api, which, canvas, last, x, y, x, y, update_rect);
+}
+
+void rotate_release(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED,
+                 SDL_Surface * canvas,
+                 SDL_Surface * last ATTRIBUTE_UNUSED, int x, int y, SDL_Rect * update_rect)
+{
+  /* Final rotation work; and now, record the final angle
+   * we landed at, so we can reuse it -- both for stacking up
+   * the rotation as the user clicks/drags/releases repeatedly,
+   * but also so the canvas can be re-rotated to the same angle
+   * if the background color gets changed in the meantime. */
+  rotate_last_angle = do_rotate(canvas, x, y, SMOOTHING_ON);
+
+  update_rect->x = 0;
+  update_rect->y = 0;
+  update_rect->w = canvas->w;
+  update_rect->h = canvas->h;
+}
+
+void rotate_shutdown(magic_api * api ATTRIBUTE_UNUSED)
+{
+  if (rotate_snd != NULL)
+    Mix_FreeChunk(rotate_snd);
+
+  if (rotate_snapshot != NULL)
+  {
+    SDL_FreeSurface(rotate_snapshot);
+    rotate_snapshot = NULL;
+  }
+}
+
+void rotate_set_color(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED, SDL_Surface * canvas,
+                   SDL_Surface * last ATTRIBUTE_UNUSED, Uint8 r, Uint8 g, Uint8 b, SDL_Rect * update_rect)
+{
+  /* Record the new color */
+  rotate_color = SDL_MapRGB(canvas->format, r, g, b);
+
+  /* If we've been rotating the canvas, go ahead and
+   * re-rotate it at the same angle (using canvas center as
+   * a way to make `do_rotate()` calculate a 0-radian rotation);
+   * we'll render it with the new background color. */
+  if (rotate_clicked_since_switchin)
+  {
+    do_rotate(canvas, canvas->w / 2, canvas->h / 2, SMOOTHING_ON);
+    update_rect->x = 0;
+    update_rect->y = 0;
+    update_rect->w = canvas->w;
+    update_rect->h = canvas->h;
+  }
+}
+
+int rotate_requires_colors(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED)
+{
+  return 1;
+}
+
+void rotate_switchin(magic_api * api ATTRIBUTE_UNUSED,
+                  int which ATTRIBUTE_UNUSED, int mode ATTRIBUTE_UNUSED, SDL_Surface * canvas)
+{
+  if (rotate_snapshot == NULL)
+    rotate_snapshot = SDL_CreateRGBSurface(SDL_SWSURFACE, canvas->w, canvas->h,
+                                           canvas->format->BitsPerPixel, canvas->format->Rmask,
+                                           canvas->format->Gmask, canvas->format->Bmask, canvas->format->Amask);
+
+  if (rotate_snapshot != NULL)
+  {
+    SDL_BlitSurface(canvas, NULL, rotate_snapshot, NULL);
+  }
+
+  /* Our first time [back].  We haven't clicked yet,
+   * and our current rotation is 0 radians */
+  rotate_clicked_since_switchin = 0;
+  rotate_last_angle = 0.0;
+}
+
+void rotate_switchout(magic_api * api ATTRIBUTE_UNUSED,
+                   int which ATTRIBUTE_UNUSED, int mode ATTRIBUTE_UNUSED, SDL_Surface * canvas ATTRIBUTE_UNUSED)
+{
+  /* Since `set_color()` gets called _before_ `switchin()`
+   * we need to clear this flag on our way out, so we don't
+   * draw the rotated canvas again, THEN take a new snapshot,
+   * and hence undo anything that was done while we were away
+   * from this tool! */
+  rotate_clicked_since_switchin = 0;
+}
+
+int rotate_modes(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED)
+{
+  return MODE_PAINT;
+}
+
+
+Uint8 rotate_accepted_sizes(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED, int mode ATTRIBUTE_UNUSED)
+{
+  return 0;
+}
+
+Uint8 rotate_default_size(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED, int mode ATTRIBUTE_UNUSED)
+{
+  return 0;
+}
+
+void rotate_set_size(magic_api * api ATTRIBUTE_UNUSED, int which ATTRIBUTE_UNUSED, int mode ATTRIBUTE_UNUSED,
+                  SDL_Surface * canvas ATTRIBUTE_UNUSED, SDL_Surface * last ATTRIBUTE_UNUSED,
+                  Uint8 size ATTRIBUTE_UNUSED, SDL_Rect * update_rect ATTRIBUTE_UNUSED)
+{
+}

src/org.tuxpaint.Tuxpaint.appdata.xml.in

@@ -47,10 +47,10 @@
     </screenshot>
   </screenshots>
   <releases>
-    <release version="0.9.34" date="2024-09-23">
+    <release version="0.9.34" date="2024-09-24">
       <description>
         <p>New Fill mode: "Eraser" flood fill.</p>
-        <p>New Magic tools: "Comic dots" and various "Fractals".</p>
+        <p>New Magic tools: "Comic dots", "Rotate", and various "Fractals".</p>
         <p>New brush: Fluff (gradient).</p>
       </description>
     </release>