Simplify image transforms

* src/image.c: (image_set_rotation, image_set_size,
image_set_transform): Combine into image_set_transform.
(image_set_crop): Remove function.
(lookup_image): Remove calls to removed functions and remove
transform_matrix.
* test/manual/image-transforms-tests.el (test-cropping): Remove
function.
(test-transforms): Remove reference to test-cropping.

1 files changed, 98 insertions, 212 deletions

diff --git a/src/image.c b/src/image.c
index a3747cfa6b7..8b571dd72d6 100644
--- a/src/image.c
+++ b/src/image.c
@@ -1967,8 +1967,7 @@ compute_image_size (size_t width, size_t height,
 }
 #endif /* HAVE_IMAGEMAGICK || HAVE_NATIVE_TRANSFORMS */
 
-/* image_set_rotation, image_set_crop, image_set_size and
-   image_set_transform use affine transformation matrices to perform
+/* image_set_transform uses affine transformation matrices to perform
    various transforms on the image.  The matrix is a 2D array of
    doubles.  It is laid out like this:
 
@@ -2039,10 +2038,6 @@ compute_image_size (size_t width, size_t height,
    finally move the origin back to the top left of the image, which
    may now be a different corner.
 
-   Cropping is easier as we just move the origin to the top left of
-   where we want to crop and set the width and height accordingly.
-   The matrices don’t know anything about width and height.
-
    It's possible to pre-calculate the matrix multiplications and just
    generate one transform matrix that will do everything we need in a
    single step, but the maths for each element is much more complex
@@ -2070,7 +2065,7 @@ matrix3x3_mult (matrix3x3 a, matrix3x3 b, matrix3x3 result)
 }
 
 static void
-image_set_rotation (struct image *img, matrix3x3 tm)
+image_set_transform (struct frame *f, struct image *img)
 {
 #ifdef HAVE_NATIVE_TRANSFORMS
 # ifdef HAVE_IMAGEMAGICK
@@ -2084,217 +2079,112 @@ image_set_rotation (struct image *img, matrix3x3 tm)
     return;
 # endif
 
-  int rotation, cos_r, sin_r, width, height;
+  /* This is the transformation matrix we will use through all the
+     calculations.  */
+  matrix3x3 tm = { [0][0] = 1, [1][1] = 1, [2][2] = 1 };
 
+  /* Calculate image rotation.  */
   Lisp_Object value = image_spec_value (img->spec, QCrotation, NULL);
-  if (! NUMBERP (value))
-    return;
-
-  Lisp_Object reduced_angle = Fmod (value, make_fixnum (360));
-  if (! FLOATP (reduced_angle))
-    rotation = XFIXNUM (reduced_angle);
-  else
-    {
-      rotation = XFLOAT_DATA (reduced_angle);
-      if (rotation != XFLOAT_DATA (reduced_angle))
-        goto not_a_multiple_of_90;
-    }
-
-  if (rotation == 0)
-    return;
-
-  if (rotation == 90)
-    {
-      width = img->height;
-      height = img->width;
-
-      cos_r = 0;
-      sin_r = 1;
-    }
-  else if (rotation == 180)
-    {
-      width = img->width;
-      height = img->height;
-
-      cos_r = -1;
-      sin_r = 0;
-    }
-  else if (rotation == 270)
+  if (NUMBERP (value))
     {
-      width = img->height;
-      height = img->width;
+      int rotation, cos_r, sin_r, width, height;
 
-      cos_r = 0;
-      sin_r = -1;
-    }
-  else
-    {
-    not_a_multiple_of_90:
-      image_error ("Native image rotation supports "
-                   "only multiples of 90 degrees");
-      return;
-    }
-
-  /* Translate so (0, 0) is in the center of the image.  */
-  matrix3x3 t
-    = { [0][0] = 1,
-                                  [1][1] = 1,
-        [2][0] = img->width >> 1, [2][1] = img->height >> 1, [2][2] = 1 };
-  matrix3x3 tmp;
-  matrix3x3_mult (t, tm, tmp);
-
-  /* Rotate.  */
-  matrix3x3 rot = { [0][0] = cos_r, [0][1] = -sin_r,
-                    [1][0] = sin_r, [1][1] = cos_r,
-                                                     [2][2] = 1 };
-  matrix3x3 tmp2;
-  matrix3x3_mult (rot, tmp, tmp2);
-
-  /* Translate back.  */
-  t[2][0] = - (width >> 1);
-  t[2][1] = - (height >> 1);
-  matrix3x3_mult (t, tmp2, tm);
-
-  img->width = width;
-  img->height = height;
-#endif
-}
-
-static void
-image_set_crop (struct image *img, matrix3x3 tm)
-{
-#ifdef HAVE_NATIVE_TRANSFORMS
-# ifdef HAVE_IMAGEMAGICK
-  /* ImageMagick images are already cropped.  */
-  if (EQ (image_spec_value (img->spec, QCtype, NULL), Qimagemagick))
-    return;
-# endif
-
-# if !defined USE_CAIRO && defined HAVE_XRENDER
-  if (!img->picture)
-    return;
-# endif
-
-  Lisp_Object crop = image_spec_value (img->spec, QCcrop, NULL);
-
-  if (!CONSP (crop))
-    return;
-
-  Lisp_Object w = XCAR (crop), h = Qnil, x = Qnil, y = Qnil;
-  crop = XCDR (crop);
-  if (CONSP (crop))
-    {
-      h = XCAR (crop);
-      crop = XCDR (crop);
-      if (CONSP (crop))
-        {
-          x = XCAR (crop);
-          crop = XCDR (crop);
-          if (CONSP (crop))
-            y = XCAR (crop);
-        }
-    }
+      Lisp_Object reduced_angle = Fmod (value, make_fixnum (360));
+      if (! FLOATP (reduced_angle))
+        rotation = XFIXNUM (reduced_angle);
+      else
+        {
+          rotation = XFLOAT_DATA (reduced_angle);
+          if (rotation != XFLOAT_DATA (reduced_angle))
+            goto not_a_multiple_of_90;
+        }
 
-  int width = img->width;
-  if (FIXNATP (w) && XFIXNAT (w) < img->width)
-    width = XFIXNAT (w);
-  int left;
-  if (TYPE_RANGED_FIXNUMP (int, x))
-    {
-      left = XFIXNUM (x);
-      if (left < 0)
-        left = img->width - width + left;
-    }
-  else
-    left = (img->width - width) >> 1;
+      if (rotation != 0)
+        {
+          if (rotation == 90)
+            {
+              width = img->height;
+              height = img->width;
 
-  int height = img->height;
-  if (FIXNATP (h) && XFIXNAT (h) < img->height)
-    height = XFIXNAT (h);
-  int top;
-  if (TYPE_RANGED_FIXNUMP (int, y))
-    {
-      top = XFIXNUM (y);
-      if (top < 0)
-        top = img->height - height + top;
-    }
-  else
-    top = (img->height - height) >> 1;
+              cos_r = 0;
+              sin_r = 1;
+            }
+          else if (rotation == 180)
+            {
+              width = img->width;
+              height = img->height;
 
-  /* Negative values operate from the right and bottom of the image
-     instead of the left and top.  */
-  if (left < 0)
-    {
-      width = img->width + left;
-      left = 0;
-    }
+              cos_r = -1;
+              sin_r = 0;
+            }
+          else if (rotation == 270)
+            {
+              width = img->height;
+              height = img->width;
 
-  if (width + left > img->width)
-    width = img->width - left;
+              cos_r = 0;
+              sin_r = -1;
+            }
+          else
+            {
+            not_a_multiple_of_90:
+              image_error ("Native image rotation supports "
+                           "only multiples of 90 degrees");
+              return;
+            }
 
-  if (top < 0)
-    {
-      height = img->height + top;
-      top = 0;
+          /* Translate so (0, 0) is in the center of the image.  */
+          matrix3x3 t
+            = { [0][0] = 1,             [2][0] = img->width >> 1,
+                            [1][1] = 1, [2][1] = img->height >> 1,
+                                        [2][2] = 1 };
+          matrix3x3 tmp;
+          matrix3x3_mult (t, tm, tmp);
+
+          /* Rotate.  */
+          matrix3x3 rot = { [0][0] = cos_r,  [1][0] = sin_r,
+                            [0][1] = -sin_r, [1][1] = cos_r,
+                                                             [2][2] = 1 };
+          matrix3x3 tmp2;
+          matrix3x3_mult (rot, tmp, tmp2);
+
+          /* Translate back.  */
+          t[2][0] = - (width >> 1);
+          t[2][1] = - (height >> 1);
+          matrix3x3_mult (t, tmp2, tm);
+
+          img->width = width;
+          img->height = height;
+        }
     }
 
-  if (height + top > img->height)
-    height = img->height - top;
-
-  matrix3x3 tmp, m = { [0][0] = 1,
-                                      [1][1] = 1,
-                       [2][0] = left, [2][1] = top, [2][2] = 1 };
-  matrix3x3_mult (m, tm, tmp);
-  matrix3x3_copy (tmp, tm);
-
-  img->width = width;
-  img->height = height;
-#endif
-}
-
-static void
-image_set_size (struct image *img, matrix3x3 tm)
-{
-#ifdef HAVE_NATIVE_TRANSFORMS
-# ifdef HAVE_IMAGEMAGICK
-  /* ImageMagick images are already the correct size.  */
-  if (EQ (image_spec_value (img->spec, QCtype, NULL), Qimagemagick))
-    return;
-# endif
-
-# if !defined USE_CAIRO && defined HAVE_XRENDER
-  if (!img->picture)
-    return;
-# endif
-
-  int width, height;
+  /* Calculate final image size.  */
+  {
+    int width, height;
 
-  compute_image_size (img->width, img->height, img->spec, &width, &height);
+    compute_image_size (img->width, img->height, img->spec, &width, &height);
 
-  double xscale = img->width / (double) width;
-  double yscale = img->height / (double) height;
+    if (img->width != width || img->height != height)
+      {
+        double xscale = img->width / (double) width;
+        double yscale = img->height / (double) height;
 
-  matrix3x3 tmp, rm = { [0][0] = xscale, [1][1] = yscale, [2][2] = 1 };
-  matrix3x3_mult (rm, tm, tmp);
-  matrix3x3_copy (tmp, tm);
+        matrix3x3 tmp, rm = { [0][0] = xscale, [1][1] = yscale, [2][2] = 1 };
+        matrix3x3_mult (rm, tm, tmp);
+        matrix3x3_copy (tmp, tm);
 
-  img->width = width;
-  img->height = height;
-#endif
-}
+        img->width = width;
+        img->height = height;
+      }
+  }
 
-static void
-image_set_transform (struct frame *f, struct image *img, matrix3x3 matrix)
-{
-  /* TODO: Add MS Windows support.  */
-#ifdef HAVE_NATIVE_TRANSFORMS
 # if defined (HAVE_NS)
   /* Under NS the transform is applied to the drawing surface at
      drawing time, so store it for later.  */
-  ns_image_set_transform (img->pixmap, matrix);
+  ns_image_set_transform (img->pixmap, tm);
 # elif defined USE_CAIRO
-  cairo_matrix_t cr_matrix = {matrix[0][0], matrix[0][1], matrix[1][0],
-                              matrix[1][1], matrix[2][0], matrix[2][1]};
+  cairo_matrix_t cr_matrix = {tm[0][0], tm[0][1], tm[1][0],
+                              tm[1][1], tm[2][0], tm[2][1]};
   cairo_pattern_t *pattern = cairo_pattern_create_rgb (0, 0, 0);
   cairo_pattern_set_matrix (pattern, &cr_matrix);
   /* Dummy solid color pattern just to record pattern matrix.  */
@@ -2303,15 +2193,15 @@ image_set_transform (struct frame *f, struct image *img, matrix3x3 matrix)
   if (img->picture)
     {
       XTransform tmat
-        = {{{XDoubleToFixed (matrix[0][0]),
-             XDoubleToFixed (matrix[1][0]),
-             XDoubleToFixed (matrix[2][0])},
-            {XDoubleToFixed (matrix[0][1]),
-             XDoubleToFixed (matrix[1][1]),
-             XDoubleToFixed (matrix[2][1])},
-            {XDoubleToFixed (matrix[0][2]),
-             XDoubleToFixed (matrix[1][2]),
-             XDoubleToFixed (matrix[2][2])}}};
+        = {{{XDoubleToFixed (tm[0][0]),
+             XDoubleToFixed (tm[1][0]),
+             XDoubleToFixed (tm[2][0])},
+            {XDoubleToFixed (tm[0][1]),
+             XDoubleToFixed (tm[1][1]),
+             XDoubleToFixed (tm[2][1])},
+            {XDoubleToFixed (tm[0][2]),
+             XDoubleToFixed (tm[1][2]),
+             XDoubleToFixed (tm[2][2])}}};
 
       XRenderSetPictureFilter (FRAME_X_DISPLAY (f), img->picture, FilterBest,
                                0, 0);
@@ -2377,11 +2267,7 @@ lookup_image (struct frame *f, Lisp_Object spec)
           int relief_bound;
 
 #ifdef HAVE_NATIVE_TRANSFORMS
-          matrix3x3 transform_matrix = { [0][0] = 1, [1][1] = 1, [2][2] = 1 };
-          image_set_size (img, transform_matrix);
-          image_set_crop (img, transform_matrix);
-          image_set_rotation (img, transform_matrix);
-          image_set_transform (f, img, transform_matrix);
+          image_set_transform (f, img);
 #endif
 
           ascent = image_spec_value (spec, QCascent, NULL);