Blending Modes in WPF using ShaderEffect's

With the RTM of .NET 3.5 SP1 , we can now create hardware accelerated layer blending effects in WPF like those available in Image Editing tools & Photoshop & GIMP

some of the common blending modes are

Darken, Darker Colors preferred.	sampler2D input : register(s0); sampler2D tex1 : register(s1); float4 main(float2 uv : TEXCOORD) : COLOR { float4 clr1; clr1= tex2D(tex1, uv.xy); float4 Color; Color= tex2D( input , uv.xy); if (Color.r>clr1.r) Color.r=clr1.r; if (Color.g>clr1.g) Color.g=clr1.g; if (Color.b>clr1.b) Color.b=clr1.b; return Color; }
Lighten, Lighter Colors preferred.	sampler2D input : register(s0); sampler2D tex1 : register(s1); float4 main(float2 uv : TEXCOORD) : COLOR { float4 clr1; clr1= tex2D(tex1, uv.xy); float4 Color; Color= tex2D( input , uv.xy); if (Color.r<clr1.r) Color.r=clr1.r; if (Color.g<clr1.g) Color.g=clr1.g; if (Color.b<clr1.b) Color.b=clr1.b; return Color; }
Difference, Simple Arithmetic difference on color components.	sampler2D input : register(s0); sampler2D tex1 : register(s1); float4 main(float2 uv : TEXCOORD) : COLOR { float4 clr1; clr1= tex2D(tex1, uv.xy); float4 Color; Color= tex2D( input , uv.xy); Color.r=clr1.r - Color.r; Color.g=clr1.g - Color.g; Color.b=clr1.b - Color.b; return Color; }
Multiply, Simple Arithmetic Multiplication on color components.	sampler2D input : register(s0); sampler2D tex1 : register(s1); float4 main(float2 uv : TEXCOORD) : COLOR { float4 clr1; clr1= tex2D(tex1, uv.xy); float4 Color; Color= tex2D( input , uv.xy); Color.r=clr1.r * Color.r; Color.g=clr1.g * Color.g; Color.b=clr1.b * Color.b; return Color; }
NegationDifference, opposite or negative of difference	sampler2D input : register(s0); sampler2D tex1 : register(s1); float4 main(float2 uv : TEXCOORD) : COLOR { float4 clr1; clr1= tex2D(tex1, uv.xy); float4 Color; Color= tex2D( input , uv.xy); Color.r=1-(1-clr1.r - Color.r); Color.g=1-(1-clr1.g - Color.g); Color.b=1-(1-clr1.b - Color.b); return Color; }
Overlay Hardlight, Combination of Multiply for darer colors and NegationDifference for Lighter colors.	sampler2D input : register(s0); sampler2D tex1 : register(s1); float4 main(float2 uv : TEXCOORD) : COLOR { float4 clr1; clr1= tex2D(tex1, uv.xy); float4 Color; Color= tex2D( input , uv.xy); if (Color.r<0.5) Color.r=clr1.r * Color.r; else Color.r=1-((1-Color.r)*(1-clr1.r)); if (Color.g<0.5) Color.g=clr1.g * Color.g; else Color.g=1-((1-Color.g)*(1-clr1.g)); if (Color.b<0.5) Color.b=clr1.b * Color.b; else Color.b=1-((1-Color.b)*(1-clr1.b)); return Color; }
Overlay SoftLight, Variation on Overlay for Lighter colors.	sampler2D input : register(s0); sampler2D tex1 : register(s1); float4 main(float2 uv : TEXCOORD) : COLOR { float c=0; float4 clr1; clr1= tex2D(tex1, uv.xy); float4 Color; Color= tex2D( input , uv.xy); c=clr1.r * Color.r; Color.r=c+Color.r*(1-((1-Color.r)*(1-clr1.r)-c)); c=clr1.g * Color.g; Color.g=c+Color.g*(1-((1-Color.g)*(1-clr1.g)-c)); c=clr1.b * Color.b; Color.b=c+Color.b*(1-((1-Color.b)*(1-clr1.b)-c)); return Color; }
Exclusion	sampler2D input : register(s0); sampler2D tex1 : register(s1); float4 main(float2 uv : TEXCOORD) : COLOR { float4 clr1; clr1= tex2D(tex1, uv.xy); float4 Color; Color= tex2D( input , uv.xy); Color.r+=clr1.r-clr1.r * Color.r; Color.g+=clr1.g-clr1.g * Color.g; Color.b+=clr1.b-clr1.b * Color.b; return Color; }

Download ShaderPad and play with these effects..