Add std/gif comment about clipping to image rect
diff --git a/std/gif/decode_gif.wuffs b/std/gif/decode_gif.wuffs
index 90ca753..44eefac 100644
--- a/std/gif/decode_gif.wuffs
+++ b/std/gif/decode_gif.wuffs
@@ -364,9 +364,15 @@
}
pub func decoder.frame_dirty_rect() base.rect_ie_u32 {
- // TODO: intersect this with the frame_rect? In theory, that should be
- // unnecessary, and could hide bugs, but it'd be a cheap way to ensure that
- // the dirty_rect is inside the frame_rect.
+ // The "foo.min(x:this.width_or_height)" calls clip the nominal frame_rect
+ // to the image_rect. The "x" argument name doesn't necessarily mean "the x
+ // direction". It's just that, in Wuffs, every function call argument needs
+ // a name, and for the min function, "x" is as good a name as any other.
+ //
+ // TODO: explicitly intersect this with the frame_rect (in the y
+ // direction)? In theory, that should be unnecessary, and could hide bugs,
+ // but it'd be a cheap way to ensure that the dirty_rect is inside the
+ // frame_rect.
//
// Note that this method is pure, so it cannot set a sticky error bit if
// the dirty_rect is too big.
@@ -446,6 +452,11 @@
}
if args.dst <> nullptr {
+ // The "foo.min(x:this.width_or_height)" calls clip the nominal
+ // frame_rect to the image_rect. The "x" argument name doesn't
+ // necessarily mean "the x direction". It's just that, in Wuffs, every
+ // function call argument needs a name, and for the min function, "x"
+ // is as good a name as any other.
args.dst.update!(bounds:this.util.make_rect_ie_u32(
min_incl_x:this.frame_rect_x0.min(x:this.width),
min_incl_y:this.frame_rect_y0.min(x:this.height),
