From 0474a0d7d4478e967c7bbee93ab3606f0b215e66 Mon Sep 17 00:00:00 2001
From: Alan Third <alan@idiocy.org>
Date: Wed, 10 Feb 2021 22:12:16 +0000
Subject: [PATCH] Remove aliasing on SVG images under scaled NS frames

* src/image.c (FRAME_SCALE_FACTOR): New #define for getting frame
scale factor.
(image_set_transform):
(svg_load_image): Use FRAME_SCALE_FACTOR.
* src/nsterm.m (ns_frame_scale_factor): Get the scale factor for an NS
frame.
---
 src/image.c  | 13 +++++++++++--
 src/nsterm.h |  1 +
 src/nsterm.m | 11 +++++++++++
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/image.c b/src/image.c
index a124cf91ba0..8137dbea8d7 100644
--- a/src/image.c
+++ b/src/image.c
@@ -135,6 +135,12 @@ typedef struct ns_bitmap_record Bitmap_Record;
 # define COLOR_TABLE_SUPPORT 1
 #endif
 
+#if defined HAVE_NS
+# define FRAME_SCALE_FACTOR(f) ns_frame_scale_factor (f)
+#else
+# define FRAME_SCALE_FACTOR(f) 1;
+#endif
+
 static void image_disable_image (struct frame *, struct image *);
 static void image_edge_detection (struct frame *, struct image *, Lisp_Object,
                                   Lisp_Object);
@@ -2207,8 +2213,8 @@ image_set_transform (struct frame *f, struct image *img)
   /* SVGs are pre-scaled to the correct size.  */
   if (EQ (image_spec_value (img->spec, QCtype, NULL), Qsvg))
     {
-      width = img->width;
-      height = img->height;
+      width = img->width / FRAME_SCALE_FACTOR (f);
+      height = img->height / FRAME_SCALE_FACTOR (f);
     }
   else
 #endif
@@ -10008,6 +10014,9 @@ svg_load_image (struct frame *f, struct image *img, char *contents,
   compute_image_size (viewbox_width, viewbox_height, img->spec,
                       &width, &height);
 
+  width *= FRAME_SCALE_FACTOR (f);
+  height *= FRAME_SCALE_FACTOR (f);
+
   if (! check_image_size (f, width, height))
     {
       image_size_error ();
diff --git a/src/nsterm.h b/src/nsterm.h
index eae1d0725ea..017c2394ef1 100644
--- a/src/nsterm.h
+++ b/src/nsterm.h
@@ -1252,6 +1252,7 @@ struct input_event;
 extern void ns_init_events (struct input_event *);
 extern void ns_finish_events (void);
 
+extern double ns_frame_scale_factor (struct frame *);
 
 #ifdef NS_IMPL_GNUSTEP
 extern char gnustep_base_version[];  /* version tracking */
diff --git a/src/nsterm.m b/src/nsterm.m
index 1b2328628ee..ca240eb55f1 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -857,6 +857,17 @@ ns_row_rect (struct window *w, struct glyph_row *row,
 }
 
 
+double
+ns_frame_scale_factor (struct frame *f)
+{
+#if defined (NS_IMPL_COCOA) && MAC_OS_X_VERSION_MAX_ALLOWED > 1060
+  return [[FRAME_NS_VIEW (f) window] backingScaleFactor];
+#else
+  return [[FRAME_NS_VIEW (f) window] userSpaceScaleFactor];
+#endif
+}
+
+
 /* ==========================================================================
 
     Focus (clipping) and screen update
-- 
2.39.2