Added some more filters for testing.

On image insert, the image Red and Blue channel are swapped. Now you can
swap em back:)

paint.pro

@@ -170,5 +170,8 @@ TRANSLATIONS += i18n/*.ts
 RESOURCES +=
 
 DISTFILES += \
-    qml/components/ClipboardCanvas.qml
+    qml/components/ClipboardCanvas.qml \
+    qml/glsl/swap_RGB-BGR.frag \
+    qml/glsl/swap_RGB-GBR.frag \
+    qml/glsl/swap_RGB-RBG.frag
 

qml/glsl/swap_RGB-BGR.frag

@@ -0,0 +1,16 @@
+// Swap color channels RGB --> BGR
+
+precision mediump float;
+
+uniform sampler2D source;
+uniform sampler2D mask;
+varying highp vec2 qt_TexCoord0;
+uniform lowp float qt_Opacity;
+
+void main(void)
+{
+    if (texture2D(mask, qt_TexCoord0.st).a > 0.5)
+        gl_FragColor = texture2D(source, qt_TexCoord0.st).bgra * qt_Opacity;
+    else
+        gl_FragColor = texture2D(source, qt_TexCoord0.st) * qt_Opacity;
+}

qml/glsl/swap_RGB-GBR.frag

@@ -0,0 +1,16 @@
+// Swap color channels RGB --> GBR
+
+precision mediump float;
+
+uniform sampler2D source;
+uniform sampler2D mask;
+varying highp vec2 qt_TexCoord0;
+uniform lowp float qt_Opacity;
+
+void main(void)
+{
+    if (texture2D(mask, qt_TexCoord0.st).a > 0.5)
+        gl_FragColor = texture2D(source, qt_TexCoord0.st).gbra * qt_Opacity;
+    else
+        gl_FragColor = texture2D(source, qt_TexCoord0.st) * qt_Opacity;
+}

qml/glsl/swap_RGB-RBG.frag

@@ -0,0 +1,16 @@
+// Swap color channels RGB --> RBG
+
+precision mediump float;
+
+uniform sampler2D source;
+uniform sampler2D mask;
+varying highp vec2 qt_TexCoord0;
+uniform lowp float qt_Opacity;
+
+void main(void)
+{
+    if (texture2D(mask, qt_TexCoord0.st).a > 0.5)
+        gl_FragColor = texture2D(source, qt_TexCoord0.st).rbga * qt_Opacity;
+    else
+        gl_FragColor = texture2D(source, qt_TexCoord0.st) * qt_Opacity;
+}