Photoshop如何将两个图像混合在一起?

有人可以解释一下Photoshop如何将两幅图像混合在一起,以便在应用程序中重现相同的效果。

Photoshop通过对图像A中的每个像素对图像B中的相应像素执行混合操作来将两个图像混合在一起。每个像素是由多个通道组成的颜色。 假设我们正在处理RGB像素,每个像素的通道将是红色,绿色和蓝色。 要混合两个像素,我们混合各自的通道。

Photoshop中每种混合模式的混合操作都可以归纳为以下macros:

#define ChannelBlend_Normal(A,B) ((uint8)(A)) #define ChannelBlend_Lighten(A,B) ((uint8)((B > A) ? B:A)) #define ChannelBlend_Darken(A,B) ((uint8)((B > A) ? A:B)) #define ChannelBlend_Multiply(A,B) ((uint8)((A * B) / 255)) #define ChannelBlend_Average(A,B) ((uint8)((A + B) / 2)) #define ChannelBlend_Add(A,B) ((uint8)(min(255, (A + B)))) #define ChannelBlend_Subtract(A,B) ((uint8)((A + B < 255) ? 0:(A + B - 255))) #define ChannelBlend_Difference(A,B) ((uint8)(abs(A - B))) #define ChannelBlend_Negation(A,B) ((uint8)(255 - abs(255 - A - B))) #define ChannelBlend_Screen(A,B) ((uint8)(255 - (((255 - A) * (255 - B)) >> 8))) #define ChannelBlend_Exclusion(A,B) ((uint8)(A + B - 2 * A * B / 255)) #define ChannelBlend_Overlay(A,B) ((uint8)((B < 128) ? (2 * A * B / 255):(255 - 2 * (255 - A) * (255 - B) / 255))) #define ChannelBlend_SoftLight(A,B) ((uint8)((B < 128)?(2*((A>>1)+64))*((float)B/255):(255-(2*(255-((A>>1)+64))*(float)(255-B)/255)))) #define ChannelBlend_HardLight(A,B) (ChannelBlend_Overlay(B,A)) #define ChannelBlend_ColorDodge(A,B) ((uint8)((B == 255) ? B:min(255, ((A << 8 ) / (255 - B))))) #define ChannelBlend_ColorBurn(A,B) ((uint8)((B == 0) ? B:max(0, (255 - ((255 - A) << 8 ) / B)))) #define ChannelBlend_LinearDodge(A,B)(ChannelBlend_Add(A,B)) #define ChannelBlend_LinearBurn(A,B) (ChannelBlend_Subtract(A,B)) #define ChannelBlend_LinearLight(A,B)((uint8)(B < 128)?ChannelBlend_LinearBurn(A,(2 * B)):ChannelBlend_LinearDodge(A,(2 * (B - 128)))) #define ChannelBlend_VividLight(A,B) ((uint8)(B < 128)?ChannelBlend_ColorBurn(A,(2 * B)):ChannelBlend_ColorDodge(A,(2 * (B - 128)))) #define ChannelBlend_PinLight(A,B) ((uint8)(B < 128)?ChannelBlend_Darken(A,(2 * B)):ChannelBlend_Lighten(A,(2 * (B - 128)))) #define ChannelBlend_HardMix(A,B) ((uint8)((ChannelBlend_VividLight(A,B) < 128) ? 0:255)) #define ChannelBlend_Reflect(A,B) ((uint8)((B == 255) ? B:min(255, (A * A / (255 - B))))) #define ChannelBlend_Glow(A,B) (ChannelBlend_Reflect(B,A)) #define ChannelBlend_Phoenix(A,B) ((uint8)(min(A,B) - max(A,B) + 255)) #define ChannelBlend_Alpha(A,B,O) ((uint8)(O * A + (1 - O) * B)) #define ChannelBlend_AlphaF(A,B,F,O) (ChannelBlend_Alpha(F(A,B),A,O)) 

要混合一个RGB像素,您可以执行以下操作:

 ImageTColorR = ChannelBlend_Glow(ImageAColorR, ImageBColorR); ImageTColorB = ChannelBlend_Glow(ImageAColorB, ImageBColorB); ImageTColorG = ChannelBlend_Glow(ImageAColorG, ImageBColorG); ImageTColor = RGB(ImageTColorR, ImageTColorB, ImageTColorG); 

如果我们想要以特定的不透明度进行混合操作,比如说50%:

 ImageTColorR = ChannelBlend_AlphaF(ImageAColorR, ImageBColorR, Blend_Subtract, 0.5F); 

如果您有指向图像A,B和T(我们的目标)的图像数据的指针,我们可以使用此macros简化所有三个通道的混合:

 #define ColorBlend_Buffer(T,A,B,M) (T)[0] = ChannelBlend_##M((A)[0], (B)[0]), (T)[1] = ChannelBlend_##M((A)[1], (B)[1]), (T)[2] = ChannelBlend_##M((A)[2], (B)[2]) 

并且可以导出下列RGB颜色混合macros:

 #define ColorBlend_Normal(T,A,B) (ColorBlend_Buffer(T,A,B,Normal)) #define ColorBlend_Lighten(T,A,B) (ColorBlend_Buffer(T,A,B,Lighten)) #define ColorBlend_Darken(T,A,B) (ColorBlend_Buffer(T,A,B,Darken)) #define ColorBlend_Multiply(T,A,B) (ColorBlend_Buffer(T,A,B,Multiply)) #define ColorBlend_Average(T,A,B) (ColorBlend_Buffer(T,A,B,Average)) #define ColorBlend_Add(T,A,B) (ColorBlend_Buffer(T,A,B,Add)) #define ColorBlend_Subtract(T,A,B) (ColorBlend_Buffer(T,A,B,Subtract)) #define ColorBlend_Difference(T,A,B) (ColorBlend_Buffer(T,A,B,Difference)) #define ColorBlend_Negation(T,A,B) (ColorBlend_Buffer(T,A,B,Negation)) #define ColorBlend_Screen(T,A,B) (ColorBlend_Buffer(T,A,B,Screen)) #define ColorBlend_Exclusion(T,A,B) (ColorBlend_Buffer(T,A,B,Exclusion)) #define ColorBlend_Overlay(T,A,B) (ColorBlend_Buffer(T,A,B,Overlay)) #define ColorBlend_SoftLight(T,A,B) (ColorBlend_Buffer(T,A,B,SoftLight)) #define ColorBlend_HardLight(T,A,B) (ColorBlend_Buffer(T,A,B,HardLight)) #define ColorBlend_ColorDodge(T,A,B) (ColorBlend_Buffer(T,A,B,ColorDodge)) #define ColorBlend_ColorBurn(T,A,B) (ColorBlend_Buffer(T,A,B,ColorBurn)) #define ColorBlend_LinearDodge(T,A,B) (ColorBlend_Buffer(T,A,B,LinearDodge)) #define ColorBlend_LinearBurn(T,A,B) (ColorBlend_Buffer(T,A,B,LinearBurn)) #define ColorBlend_LinearLight(T,A,B) (ColorBlend_Buffer(T,A,B,LinearLight)) #define ColorBlend_VividLight(T,A,B) (ColorBlend_Buffer(T,A,B,VividLight)) #define ColorBlend_PinLight(T,A,B) (ColorBlend_Buffer(T,A,B,PinLight)) #define ColorBlend_HardMix(T,A,B) (ColorBlend_Buffer(T,A,B,HardMix)) #define ColorBlend_Reflect(T,A,B) (ColorBlend_Buffer(T,A,B,Reflect)) #define ColorBlend_Glow(T,A,B) (ColorBlend_Buffer(T,A,B,Glow)) #define ColorBlend_Phoenix(T,A,B) (ColorBlend_Buffer(T,A,B,Phoenix)) 

例如:

 ColorBlend_Glow(TargetPtr, ImageAPtr, ImageBPtr); 

其余的Photoshop混合模式涉及将RGB转换为HLS并再次返回。

 #define ColorBlend_Hue(T,A,B) ColorBlend_Hls(T,A,B,HueB,LuminationA,SaturationA) #define ColorBlend_Saturation(T,A,B) ColorBlend_Hls(T,A,B,HueA,LuminationA,SaturationB) #define ColorBlend_Color(T,A,B) ColorBlend_Hls(T,A,B,HueB,LuminationA,SaturationB) #define ColorBlend_Luminosity(T,A,B) ColorBlend_Hls(T,A,B,HueA,LuminationB,SaturationA) #define ColorBlend_Hls(T,A,B,O1,O2,O3) { float64 HueA, LuminationA, SaturationA; float64 HueB, LuminationB, SaturationL; Color_RgbToHls((A)[2],(A)[1],(A)[0], &HueA, &LuminationA, &SaturationA); Color_RgbToHls((B)[2],(B)[1],(B)[0], &HueB, &LuminationB, &SaturationB); Color_HlsToRgb(O1,O2,O3,&(T)[2],&(T)[1],&(T)[0]); } 

这些function将有助于将RGB转换为HLS。

 int32 Color_HueToRgb(float64 M1, float64 M2, float64 Hue, float64 *Channel) { if (Hue < 0.0) Hue += 1.0; else if (Hue > 1.0) Hue -= 1.0; if ((6.0 * Hue) < 1.0) *Channel = (M1 + (M2 - M1) * Hue * 6.0); else if ((2.0 * Hue) < 1.0) *Channel = (M2); else if ((3.0 * Hue) < 2.0) *Channel = (M1 + (M2 - M1) * ((2.0F / 3.0F) - Hue) * 6.0); else *Channel = (M1); return TRUE; } int32 Color_RgbToHls(uint8 Red, uint8 Green, uint8 Blue, float64 *Hue, float64 *Lumination, float64 *Saturation) { float64 Delta; float64 Max, Min; float64 Redf, Greenf, Bluef; Redf = ((float64)Red / 255.0F); Greenf = ((float64)Green / 255.0F); Bluef = ((float64)Blue / 255.0F); Max = max(max(Redf, Greenf), Bluef); Min = min(min(Redf, Greenf), Bluef); *Hue = 0; *Lumination = (Max + Min) / 2.0F; *Saturation = 0; if (Max == Min) return TRUE; Delta = (Max - Min); if (*Lumination < 0.5) *Saturation = Delta / (Max + Min); else *Saturation = Delta / (2.0 - Max - Min); if (Redf == Max) *Hue = (Greenf - Bluef) / Delta; else if (Greenf == Max) *Hue = 2.0 + (Bluef - Redf) / Delta; else *Hue = 4.0 + (Redf - Greenf) / Delta; *Hue /= 6.0; if (*Hue < 0.0) *Hue += 1.0; return TRUE; } int32 Color_HlsToRgb(float64 Hue, float64 Lumination, float64 Saturation, uint8 *Red, uint8 *Green, uint8 *Blue) { float64 M1, M2; float64 Redf, Greenf, Bluef; if (Saturation == 0) { Redf = Lumination; Greenf = Lumination; Bluef = Lumination; } else { if (Lumination <= 0.5) M2 = Lumination * (1.0 + Saturation); else M2 = Lumination + Saturation - Lumination * Saturation; M1 = (2.0 * Lumination - M2); Color_HueToRgb(M1, M2, Hue + (1.0F / 3.0F), &Redf); Color_HueToRgb(M1, M2, Hue, &Greenf); Color_HueToRgb(M1, M2, Hue - (1.0F / 3.0F), &Bluef); } *Red = (uint8)(Redf * 255); *Blue = (uint8)(Bluef * 255); *Green = (uint8)(Greenf * 255); return TRUE; } 

这个话题有更多的资源,主要是:

  1. PegTop混合模式
  2. 法医Photoshop
  3. 洞察到Photoshop 7.0混合模式
  4. SF – 基础 – 混合模式
  5. 完成混合模式
  6. 罗姆博客
  7. ReactOS RGB-HLS转换function

这个答案中的色调,颜色,饱和度混合模式是错误的。 没有Adobe产品转换成HSB,他们直接对RGB值进行操作。

以下是GLSL的设置亮度,例如:

 float lum(vec4 color) { return ((0.3 * color.r) + (0.59 * color.g) + (0.11 * color.b)); } vec4 clipColor(vec4 color) { vec4 newColor=color; float l=lum(color); float n=min(min(color.r,color.g),color.b); float x=max(max(color.r,color.g),color.b); newColor.r=(n<0.0) ? l+(((color.rl)*l)/(ln)) : color.r; newColor.r=(x>1.0) ? l+(((color.rl)*(1.0-l))/(xl)) : color.r; newColor.g=(n<0.0) ? l+(((color.gl)*l)/(ln)) : color.g; newColor.g=(x>1.0) ? l+(((color.gl)*(1.0-l))/(xl)) : color.g; newColor.b=(n<0.0) ? l+(((color.bl)*l)/(ln)) : color.b; newColor.b=(x>1.0) ? l+(((color.bl)*(1.0-l))/(xl)) : color.b; return clamp(newColor,0.0,1.0); } vec4 setlum(vec4 color, float l) { float d=l-lum(color); color.r+=d; color.g+=d; color.b+=d; return clipColor(color); } kernel vec4 blendLuminosity(sampler topimage, sampler bottomimage) { vec4 base=sample(bottomimage, samplerCoord(bottomimage)); vec4 blend=sample(topimage, samplerCoord(topimage)); float bl=lum(blend); return setlum(base,bl); } 

不支持CIKernel中的if .. else语句,因此使用三元运算符。

普遍的答案是99.9%正确,但正如Greyfriars所说,它不会得到确切的结果,因为Adobe在混合中不会使用HLS。

但是,您不需要在Adobe工作就可以做到这一点…您可以按照Adobe提供的文档中的所有规则进行完全相同的混合:

基本上第4章和第7章: http : //partners.adobe.com/public/developer/en/pdf/PDFReference.pdf

然后,您将像Adobe一样达到确切的结果! 像素由像素!

虽然stream行的答案大多是正确的,但下面的说法是错误的。 “其余的Photoshop混合模式涉及将RGB转换为HLS,然后再返回。 不,Photoshop(只有Photoshop)使用Chroma和Luma来代替HLS。

所以对于色调,颜色,亮度和饱和度模式,您不能使用简单的algorithm。 要在这些情况下匹配Photoshop的方法,您需要为Adobe工作。