Fix wide characters being cut off

Fixes #791.

2 files changed, 39 insertions, 30 deletions

diff --git a/alacritty/res/text.f.glsl b/alacritty/res/text.f.glsl
index c0c1bd1b..d5e26881 100644
--- a/alacritty/res/text.f.glsl
+++ b/alacritty/res/text.f.glsl
@@ -9,31 +9,31 @@ layout(location = 0, index = 1) out vec4 alphaMask;
 
 uniform sampler2D mask;
 
-void main()
-{
+#define COLORED 2
+
+void main() {
     if (backgroundPass != 0) {
-        if (bg.a == 0.0)
+        if (bg.a == 0.0) {
             discard;
+        }
 
         alphaMask = vec4(1.0);
         color = vec4(bg.rgb, 1.0);
-    } else {
-        if (fg.a != 0.0) {
-            // Color glyphs, like emojis.
-            vec4 glyphColor = texture(mask, TexCoords);
-            alphaMask = vec4(glyphColor.a);
+    } else if ((int(fg.a) & COLORED) != 0) {
+        // Color glyphs, like emojis.
+        vec4 glyphColor = texture(mask, TexCoords);
+        alphaMask = vec4(glyphColor.a);
 
-            // Revert alpha premultiplication.
-            if (glyphColor.a != 0) {
-                glyphColor.rgb = vec3(glyphColor.rgb / glyphColor.a);
-            }
-
-            color = vec4(glyphColor.rgb, 1.0);
-        } else {
-            // Regular text glyphs.
-            vec3 textColor = texture(mask, TexCoords).rgb;
-            alphaMask = vec4(textColor, textColor.r);
-            color = vec4(fg.rgb, 1.0);
+        // Revert alpha premultiplication.
+        if (glyphColor.a != 0) {
+            glyphColor.rgb = vec3(glyphColor.rgb / glyphColor.a);
         }
+
+        color = vec4(glyphColor.rgb, 1.0);
+    } else {
+        // Regular text glyphs.
+        vec3 textColor = texture(mask, TexCoords).rgb;
+        alphaMask = vec4(textColor, textColor.r);
+        color = vec4(fg.rgb, 1.0);
     }
 }
diff --git a/alacritty/res/text.v.glsl b/alacritty/res/text.v.glsl
index 0f5fd3f9..31e6f934 100644
--- a/alacritty/res/text.v.glsl
+++ b/alacritty/res/text.v.glsl
@@ -1,18 +1,20 @@
 #version 330 core
 // Cell properties.
-layout (location = 0) in vec2 gridCoords;
+layout(location = 0) in vec2 gridCoords;
 
 // Glyph properties.
-layout (location = 1) in vec4 glyph;
+layout(location = 1) in vec4 glyph;
 
 // uv mapping.
-layout (location = 2) in vec4 uv;
+layout(location = 2) in vec4 uv;
 
-// Text foreground rgb packed together with multicolor flag.
-layout (location = 3) in vec4 textColor;
+// Text foreground rgb packed together with cell flags. textColor.a
+// are the bitflags; consult RenderingGlyphFlags in renderer/mod.rs
+// for the possible values.
+layout(location = 3) in vec4 textColor;
 
 // Background color.
-layout (location = 4) in vec4 backgroundColor;
+layout(location = 4) in vec4 backgroundColor;
 
 out vec2 TexCoords;
 flat out vec4 fg;
@@ -24,9 +26,9 @@ uniform vec4 projection;
 
 uniform int backgroundPass;
 
+#define WIDE_CHAR 1
 
-void main()
-{
+void main() {
     vec2 projectionOffset = projection.xy;
     vec2 projectionScale = projection.zw;
 
@@ -39,8 +41,14 @@ void main()
     vec2 cellPosition = cellDim * gridCoords;
 
     if (backgroundPass != 0) {
-        vec2 finalPosition = cellPosition + cellDim * position;
-        gl_Position = vec4(projectionOffset + projectionScale * finalPosition, 0.0, 1.0);
+        vec2 backgroundDim = cellDim;
+        if ((int(textColor.a) & WIDE_CHAR) != 0) {
+            // Update wide char x dimension so it'll cover the following spacer.
+            backgroundDim.x *= 2;
+        }
+        vec2 finalPosition = cellPosition + backgroundDim * position;
+        gl_Position =
+            vec4(projectionOffset + projectionScale * finalPosition, 0.0, 1.0);
 
         TexCoords = vec2(0, 0);
     } else {
@@ -49,7 +57,8 @@ void main()
         glyphOffset.y = cellDim.y - glyphOffset.y;
 
         vec2 finalPosition = cellPosition + glyphSize * position + glyphOffset;
-        gl_Position = vec4(projectionOffset + projectionScale * finalPosition, 0.0, 1.0);
+        gl_Position =
+            vec4(projectionOffset + projectionScale * finalPosition, 0.0, 1.0);
 
         vec2 uvOffset = uv.xy;
         vec2 uvSize = uv.zw;