diff --git a/Cargo.lock b/Cargo.lock
index 0b90829ef7..e451dc71b7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1047,7 +1047,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "plane-split"
-version = "0.13.4"
+version = "0.13.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "binary-space-partition 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1621,7 +1621,7 @@ dependencies = [
  "pathfinder_gfx_utils 0.2.0 (git+https://github.com/pcwalton/pathfinder?branch=webrender)",
  "pathfinder_partitioner 0.2.0 (git+https://github.com/pcwalton/pathfinder?branch=webrender)",
  "pathfinder_path_utils 0.2.0 (git+https://github.com/pcwalton/pathfinder?branch=webrender)",
- "plane-split 0.13.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "plane-split 0.13.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "png 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1965,7 +1965,7 @@ dependencies = [
 "checksum pathfinder_path_utils 0.2.0 (git+https://github.com/pcwalton/pathfinder?branch=webrender)" = "<none>"
 "checksum percent-encoding 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "31010dd2e1ac33d5b46a5b413495239882813e0369f8ed8a5e266f173602f831"
 "checksum pkg-config 0.3.11 (registry+https://github.com/rust-lang/crates.io-index)" = "110d5ee3593dbb73f56294327fe5668bcc997897097cbc76b51e7aed3f52452f"
-"checksum plane-split 0.13.4 (registry+https://github.com/rust-lang/crates.io-index)" = "69f5ea52d7bf50ff02342f5af8527c81030bac5545e92eeeb4a2dfd7bfd2ef69"
+"checksum plane-split 0.13.6 (registry+https://github.com/rust-lang/crates.io-index)" = "b84b8cf2daa6a829b3e756fb75e0eab8e0d963754de9bfc83a4373a47121323a"
 "checksum png 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9adebf7fb91ccf5eac9da1a8e00e83cb8ae882c3e8d8e4ad59da73cb8c82a2c9"
 "checksum proc-macro2 0.4.25 (registry+https://github.com/rust-lang/crates.io-index)" = "d3797b7142c9aa74954e351fc089bbee7958cebbff6bf2815e7ffff0b19f547d"
 "checksum quick-error 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "eda5fe9b71976e62bc81b781206aaa076401769b2143379d3eb2118388babac4"
diff --git a/webrender/res/ps_text_run.glsl b/webrender/res/ps_text_run.glsl
index 1b3d1d56b0..e042df6a25 100644
--- a/webrender/res/ps_text_run.glsl
+++ b/webrender/res/ps_text_run.glsl
@@ -81,34 +81,39 @@ VertexInfo write_text_vertex(RectWithSize local_clip_rect,
     // Compute the snapping offset only if the scroll node transform is axis-aligned.
     if (remove_subpx_offset) {
         // Be careful to only snap with the transform when in screen raster space.
-        if (raster_space == RASTER_SCREEN) {
-            // Transform from local space to device space.
-            float device_scale = task.common_data.device_pixel_scale / transform.m[3].w;
-            mat2 device_transform = mat2(transform.m) * device_scale;
+        switch (raster_space) {
+            case RASTER_SCREEN: {
+                // Transform from local space to device space.
+                float device_scale = task.common_data.device_pixel_scale / transform.m[3].w;
+                mat2 device_transform = mat2(transform.m) * device_scale;
 
-            // Ensure the transformed text offset does not contain a subpixel translation
-            // such that glyph snapping is stable for equivalent glyph subpixel positions.
-            vec2 device_text_pos = device_transform * text_offset + transform.m[3].xy * device_scale;
-            snap_offset = floor(device_text_pos + 0.5) - device_text_pos;
+                // Ensure the transformed text offset does not contain a subpixel translation
+                // such that glyph snapping is stable for equivalent glyph subpixel positions.
+                vec2 device_text_pos = device_transform * text_offset + transform.m[3].xy * device_scale;
+                snap_offset = floor(device_text_pos + 0.5) - device_text_pos;
 
-            // Snap the glyph offset to a device pixel, using an appropriate bias depending
-            // on whether subpixel positioning is required.
-            vec2 device_glyph_offset = device_transform * glyph_offset;
-            snap_offset += floor(device_glyph_offset + snap_bias) - device_glyph_offset;
+                // Snap the glyph offset to a device pixel, using an appropriate bias depending
+                // on whether subpixel positioning is required.
+                vec2 device_glyph_offset = device_transform * glyph_offset;
+                snap_offset += floor(device_glyph_offset + snap_bias) - device_glyph_offset;
 
-            // Transform from device space back to local space.
-            local_transform = inverse(device_transform);
+                // Transform from device space back to local space.
+                local_transform = inverse(device_transform);
 
 #ifndef WR_FEATURE_GLYPH_TRANSFORM
-            // If not using transformed subpixels, the glyph rect is actually in local space.
-            // So convert the snap offset back to local space.
-            snap_offset = local_transform * snap_offset;
+                // If not using transformed subpixels, the glyph rect is actually in local space.
+                // So convert the snap offset back to local space.
+                snap_offset = local_transform * snap_offset;
 #endif
-        } else {
-            // Otherwise, when in local raster space, the transform may be animated, so avoid
-            // snapping with the transform to avoid oscillation.
-            snap_offset = floor(text_offset + 0.5) - text_offset;
-            snap_offset += floor(glyph_offset + snap_bias) - glyph_offset;
+                break;
+            }
+            default: {
+                // Otherwise, when in local raster space, the transform may be animated, so avoid
+                // snapping with the transform to avoid oscillation.
+                snap_offset = floor(text_offset + 0.5) - text_offset;
+                snap_offset += floor(glyph_offset + snap_bias) - glyph_offset;
+                break;
+            }
         }
     }