Fix display of sliced images on MS-Windows

* src/w32term.c (x_draw_image_foreground): Fix detection of
scaled images for sliced images.  Scale the original width of
a slice and its coordinates of origin as well.

1 files changed, 28 insertions, 10 deletions

diff --git a/src/w32term.c b/src/w32term.c
index 0f0d6482fc3..4d5f2e7c3cc 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -1896,6 +1896,24 @@ x_draw_image_foreground (struct glyph_string *s)
           orig_height = s->slice.height;
         }
 
+      double w_factor = 1.0, h_factor = 1.0;
+      bool scaled = false;
+      int orig_slice_width  = s->slice.width,
+          orig_slice_height = s->slice.height;
+      int orig_slice_x = s->slice.x, orig_slice_y = s->slice.y;
+      /* For scaled images we need to restore the original slice's
+         dimensions and origin coordinates, from before the scaling.  */
+      if (s->img->width != orig_width || s->img->height != orig_height)
+        {
+          scaled = true;
+          w_factor = (double) orig_width  / (double) s->img->width;
+          h_factor = (double) orig_height / (double) s->img->height;
+          orig_slice_width = s->slice.width * w_factor + 0.5;
+          orig_slice_height = s->slice.height * h_factor + 0.5;
+          orig_slice_x = s->slice.x * w_factor + 0.5;
+          orig_slice_y = s->slice.y * h_factor + 0.5;
+        }
+
       if (s->img->mask)
         {
           HDC mask_dc = CreateCompatibleDC (s->hdc);
@@ -1903,7 +1921,7 @@ x_draw_image_foreground (struct glyph_string *s)
 
           SetTextColor (s->hdc, RGB (255, 255, 255));
           SetBkColor (s->hdc, RGB (0, 0, 0));
-          if (s->slice.width == orig_width && s->slice.height == orig_height)
+          if (!scaled)
             {
               BitBlt (s->hdc, x, y, s->slice.width, s->slice.height,
                       compat_hdc, s->slice.x, s->slice.y, SRCINVERT);
@@ -1922,14 +1940,14 @@ x_draw_image_foreground (struct glyph_string *s)
                   && (pmode = SetStretchBltMode (s->hdc, HALFTONE)) != 0)
                 SetBrushOrgEx (s->hdc, 0, 0, NULL);
               StretchBlt (s->hdc, x, y, s->slice.width, s->slice.height,
-                          compat_hdc, s->slice.x, s->slice.y,
-                          orig_width, orig_height, SRCINVERT);
+                          compat_hdc, orig_slice_x, orig_slice_y,
+                          orig_slice_width, orig_slice_height, SRCINVERT);
               StretchBlt (s->hdc, x, y, s->slice.width, s->slice.height,
-                          mask_dc, s->slice.x, s->slice.y,
-                          orig_width, orig_height, SRCAND);
+                          mask_dc, orig_slice_x, orig_slice_y,
+                          orig_slice_width, orig_slice_height, SRCAND);
               StretchBlt (s->hdc, x, y, s->slice.width, s->slice.height,
-                          compat_hdc, s->slice.x, s->slice.y,
-                          orig_width, orig_height, SRCINVERT);
+                          compat_hdc, orig_slice_x, orig_slice_y,
+                          orig_slice_width, orig_slice_height, SRCINVERT);
               if (pmode)
                 SetStretchBltMode (s->hdc, pmode);
             }
@@ -1940,7 +1958,7 @@ x_draw_image_foreground (struct glyph_string *s)
         {
           SetTextColor (s->hdc, s->gc->foreground);
           SetBkColor (s->hdc, s->gc->background);
-          if (s->slice.width == orig_width && s->slice.height == orig_height)
+          if (!scaled)
             BitBlt (s->hdc, x, y, s->slice.width, s->slice.height,
                     compat_hdc, s->slice.x, s->slice.y, SRCCOPY);
           else
@@ -1951,8 +1969,8 @@ x_draw_image_foreground (struct glyph_string *s)
                   && (pmode = SetStretchBltMode (s->hdc, HALFTONE)) != 0)
                 SetBrushOrgEx (s->hdc, 0, 0, NULL);
               StretchBlt (s->hdc, x, y, s->slice.width, s->slice.height,
-                          compat_hdc, s->slice.x, s->slice.y,
-                          orig_width, orig_height, SRCCOPY);
+                          compat_hdc, orig_slice_x, orig_slice_y,
+                          orig_slice_width, orig_slice_height, SRCCOPY);
               if (pmode)
                 SetStretchBltMode (s->hdc, pmode);
             }