fix color bleeding

data/shaders/comp-draw.glsl

@@ -52,12 +52,15 @@ void main()
     highp vec2 uv_base = use_fragcoord ? (gl_FragCoord.st / resolution) : uv;
     highp vec4 base = texture(tex, uv_base);
     highp vec4 stroke = texture(tex_stroke, uv);
+
+    if (base.a == 0.0)
+        base.rgb = stroke.rgb;
     
-    if (stroke.a == 0.0)
-    {
-        frag = base * vec4(1.0, 1.0, 1.0, alpha);
-        return;
-    }
+    // if (stroke.a == 0.0)
+    // {
+    //     frag = base * vec4(1.0, 1.0, 1.0, alpha);
+    //     return;
+    // }
 
     if (use_pattern)
     {

data/shaders/stroke-dilate.glsl

@@ -0,0 +1,42 @@
+[[vertex]]
+
+uniform mat4 mvp;
+
+in vec4 pos;
+in vec2 uvs;
+out vec2 uv;
+
+void main()
+{
+    gl_Position = mvp * vec4(pos.xy, 0.0, 1.0);
+    uv = uvs;
+}
+
+[[fragment]]
+
+uniform sampler2D tex_bg;
+
+in highp vec2 uv;
+out highp vec4 frag;
+
+void main()
+{
+    highp vec4 bg = texture(tex_bg, uv);
+    if (bg.a == 0.0)
+    {
+        highp vec4 sum = vec4(0.0);
+        for (int y = -1; y <= 1; y++)
+        {
+            for (int x = -1; x <= 1; x++)
+            {
+                highp vec4 c = textureOffset(tex_bg, uv, ivec2(x, y));
+                sum += vec4(c.rgb * c.a, c.a);
+            }
+        }
+        frag = sum.a > 0.0 ? vec4(sum.rgb / sum.a, 0.0) : bg;
+    }
+    else
+    {
+        frag = bg;
+    }
+}

data/shaders/stroke-pad.glsl

@@ -0,0 +1,37 @@
+[[vertex]]
+
+in vec4 pos;
+out vec2 uv;
+
+void main()
+{
+    gl_Position = pos;
+    uv = pos.xy * 0.5 + 0.5;
+}
+
+[[fragment]]
+
+#include "include/ext-fb-fetch.glsl"
+
+uniform sampler2D tex_bg;
+uniform mediump vec4 col;
+
+in highp vec2 uv;
+#if defined(GL_EXT_shader_framebuffer_fetch)
+    inout highp vec4 frag;
+#else
+    out highp vec4 frag;
+#endif
+
+void main()
+{
+    // sample from the background
+#if defined(GL_EXT_shader_framebuffer_fetch)
+    highp vec4 bg = frag;
+#elif defined(GL_ARM_shader_framebuffer_fetch)
+    highp vec4 bg = gl_LastFragColorARM;
+#else
+    highp vec4 bg = texture(tex_bg, uv);
+#endif
+    frag = bg.a == 0.0 ? vec4(col.rgb, 0.0) : bg;
+}

data/shaders/stroke.glsl

@@ -61,8 +61,8 @@ void main()
     highp vec4 fg = vec4(col.rgb, brush_alpha);
 
     // early discard
-    if (fg.a == 0.0)
-        discard;
+    // if (fg.a == 0.0)
+    //     discard;
 
     if (use_pattern)
     {
@@ -86,11 +86,14 @@ void main()
     highp vec4 bg = texture(tex_bg, uv2);
 #endif
 
+    if (bg.a == 0.0)
+        bg.rgb = col.rgb;
+
     fg.a *= 1.0-rand(uv2+uv)*noise;
 
     // no need to go further
-    if (fg.a <= 0.0)
-        discard;
+    // if (fg.a <= 0.0)
+    //     discard;
 
     if (mix_alpha > 0.0)
     {

data/shaders/texture-alpha-sep.glsl

@@ -1,34 +0,0 @@
-[[vertex]]
-
-uniform mat4 mvp;
-
-in vec4 pos;
-in vec2 uvs;
-out vec2 uv;
-
-void main()
-{
-    uv = uvs;
-    gl_Position = mvp * vec4(pos.xyz, 1.0);
-}
-
-[[fragment]]
-
-uniform sampler2D tex;
-uniform sampler2D tex_alpha;
-uniform sampler2D tex_bg;
-uniform highp float alpha;
-uniform bool highlight;
-
-in highp vec2 uv;
-out highp vec4 frag;
-
-void main()
-{
-    highp vec3 rgb = texture(tex, uv).rgb;
-    highp float a = texture(tex_alpha, uv).a;
-    highp vec4 c = vec4(rgb, a);
-    frag = highlight ? 
-        vec4(clamp(vec3(0.3) + c.rgb, vec3(0.0), vec3(1.0)), c.a) : 
-        texture(tex, uv) * vec4(1.0, 1.0, 1.0, alpha);
-}

data/shaders/texture-blend.glsl

@@ -18,7 +18,6 @@ void main()
 #include "include/blend.glsl"
 
 uniform sampler2D tex;
-uniform sampler2D tex_alpha;
 uniform sampler2D tex_bg;
 uniform highp float alpha;
 uniform int blend_mode;
@@ -41,7 +40,7 @@ void main()
     highp vec4 bg = texture(tex_bg, uv);
 #endif
 
-    highp vec4 fg = vec4(texture(tex, uv).rgb, texture(tex_alpha, uv).a);
+    highp vec4 fg = texture(tex, uv);
     if (fg.a == 0.0)
     {
         frag = bg;