bug#38109: Updated Emacs to HEAD, consistently not scaling now

[Alan Third <alan@idiocy.org>]

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> It really wouldn’t surprise me too much if this was all related to
> masks, I never managed to get a satisfactory test going.
> 
> OTOH, if XPMs don’t even use these functions then that would certainly
> cause scaling to fail. I’ll have to have a look at the XPM code to
> find out what they’re doing instead.

OK, so when there’s a mask there’s a different function called in
xterm.c to draw the image. I’m not sure what the deal with that is but
I had to modify it to use x_composite_image. We also need pretty much
every other patch that we’ve posted to this thread, so I’ve attached
something that works for me.

I want to go back and add a couple of comments to it, so it’s not
final, but can you please test it and see if you can break it.

XPMs are still not scaling. I suspect PBMs are in the same boat. It
looks like the code for them creates the pixmaps themselves instead of
using image_create_x_image_and_pixmap, so they bypass the whole
XRender Picture creation. It should be relatively easy to just add in
the creation of a Picture.
-- 
Alan Third

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From 0831791c2c287c0c897ffb0b8bb35fabd890aa36 Mon Sep 17 00:00:00 2001
From: Alan Third <alan@idiocy.org>
Date: Sat, 9 Nov 2019 17:04:25 +0000
Subject: [PATCH] Fix image scaling with masks (bug#38109)

* src/image.c (image_clear_image_1): Free the XRender Pictures.
(lookup_image): Move call to image_set_transform after
postprocess_image.
(image_create_x_image_and_pixmap_1): Add 1 bit image type for masks.
* src/xterm.c (x_composite_image): Use PictOpOver when there is a mask
so the transparency is honoured.
(x_draw_image_foreground_1): Use x_composite_image.
---
 src/image.c | 36 ++++++++++++++++++++++++++++++------
 src/xterm.c |  8 ++++----
 2 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/src/image.c b/src/image.c
index 870f008b14..de883faac7 100644
--- a/src/image.c
+++ b/src/image.c
@@ -1465,6 +1465,13 @@ image_clear_image_1 (struct frame *f, struct image *img, int flags)
 	  img->ximg = NULL;
 	  img->background_valid = 0;
 	}
+# ifdef HAVE_XRENDER
+      if (img->picture)
+        {
+          XRenderFreePicture (FRAME_X_DISPLAY (f), img->picture);
+          img->picture = 0;
+        }
+# endif
 #endif
     }
 
@@ -1483,6 +1490,14 @@ image_clear_image_1 (struct frame *f, struct image *img, int flags)
 	  img->mask_img = NULL;
 	  img->background_transparent_valid = 0;
 	}
+# ifdef HAVE_XRENDER
+      if (img->mask_picture)
+        {
+          XRenderFreePicture (FRAME_X_DISPLAY (f), img->mask_picture);
+          img->mask_picture = 0;
+        }
+# endif
+
 #endif
     }
 
@@ -2244,6 +2259,14 @@ image_set_transform (struct frame *f, struct image *img)
       XRenderSetPictureFilter (FRAME_X_DISPLAY (f), img->picture, FilterBest,
 			       0, 0);
       XRenderSetPictureTransform (FRAME_X_DISPLAY (f), img->picture, &tmat);
+
+      if (img->mask_picture)
+        {
+          XRenderSetPictureFilter (FRAME_X_DISPLAY (f), img->mask_picture,
+                                   FilterBest, 0, 0);
+          XRenderSetPictureTransform (FRAME_X_DISPLAY (f), img->mask_picture,
+                                      &tmat);
+        }
     }
 # elif defined HAVE_NTGUI
   /* Store the transform matrix for application at draw time.  */
@@ -2313,10 +2336,6 @@ lookup_image (struct frame *f, Lisp_Object spec)
 	  Lisp_Object ascent, margin, relief, bg;
 	  int relief_bound;
 
-#ifdef HAVE_NATIVE_TRANSFORMS
-          image_set_transform (f, img);
-#endif
-
 	  ascent = image_spec_value (spec, QCascent, NULL);
 	  if (FIXNUMP (ascent))
 	    img->ascent = XFIXNUM (ascent);
@@ -2357,6 +2376,10 @@ lookup_image (struct frame *f, Lisp_Object spec)
 	     don't have the image yet.  */
 	  if (!EQ (builtin_lisp_symbol (img->type->type), Qpostscript))
 	    postprocess_image (f, img);
+
+#ifdef HAVE_NATIVE_TRANSFORMS
+          image_set_transform (f, img);
+#endif
 	}
 
       unblock_input ();
@@ -2585,7 +2608,7 @@ image_create_x_image_and_pixmap_1 (struct frame *f, int width, int height, int d
     {
       if (depth <= 0)
 	depth = DefaultDepthOfScreen (FRAME_X_SCREEN (f));
-      if (depth == 32 || depth == 24 || depth == 8)
+      if (depth == 32 || depth == 24 || depth == 8 || depth == 1)
         {
           XRenderPictFormat *format;
           XRenderPictureAttributes attr;
@@ -2600,7 +2623,8 @@ image_create_x_image_and_pixmap_1 (struct frame *f, int width, int height, int d
           format = XRenderFindStandardFormat (display,
                                               depth == 32 ? PictStandardARGB32
                                               : depth == 24 ? PictStandardRGB24
-                                              : PictStandardA8);
+                                              : depth == 8 ? PictStandardA8
+                                              : PictStandardA1);
           *picture = XRenderCreatePicture (display, *pixmap, format, 0, &attr);
         }
       else
diff --git a/src/xterm.c b/src/xterm.c
index 44fbd27b11..6de1644cb0 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -3056,7 +3056,7 @@ x_composite_image (struct glyph_string *s, Pixmap dest,
       destination = XRenderCreatePicture (display, dest,
                                           default_format, 0, &attr);
 
-      XRenderComposite (display, PictOpSrc,
+      XRenderComposite (display, s->img->mask_picture ? PictOpOver : PictOpSrc,
                         s->img->picture, s->img->mask_picture, destination,
                         srcX, srcY,
                         srcX, srcY,
@@ -3325,9 +3325,9 @@ x_draw_image_foreground_1 (struct glyph_string *s, Pixmap pixmap)
 	  xgcv.function = GXcopy;
 	  XChangeGC (display, s->gc, mask, &xgcv);
 
-	  XCopyArea (display, s->img->pixmap, pixmap, s->gc,
-		     s->slice.x, s->slice.y,
-		     s->slice.width, s->slice.height, x, y);
+	  x_composite_image (s, pixmap,
+                             s->slice.x, s->slice.y,
+                             x, y, s->slice.width, s->slice.height);
 	  XSetClipMask (display, s->gc, None);
 	}
       else
-- 
2.21.0