分歧色彩

分歧會將色彩元素增加或減少另一個色彩元素一定比例的量。例如，將紅色元素增加藍色元素值的一半就屬於這類變換。在這類變換中，色彩 (0.2, 0.5, 1) 會變成色彩 (0.7, 0.5, 1)。新的紅色元素為 0.2 + (1/2)(1) = 0.7。

下列範例會從 ColorBars4.bmp 檔案建構 Image 物件，然後程式碼會將上一段中所描述的分歧變換套用於影像中的每一個像素。

Dim image = New Bitmap("ColorBars.bmp")
Dim imageAttributes As New ImageAttributes()
Dim width As Integer = image.Width
Dim height As Integer = image.Height
      
Dim colorMatrixElements As Single()() = { _
   New Single() {1, 0, 0, 0, 0}, _
   New Single() {0, 1, 0, 0, 0}, _
   New Single() {0.5F, 0, 1, 0, 0}, _
   New Single() {0, 0, 0, 1, 0}, _
   New Single() {0, 0, 0, 0, 1}}
      
Dim colorMatrix As New ColorMatrix(colorMatrixElements)
      
imageAttributes.SetColorMatrix( _
   colorMatrix, _
   ColorMatrixFlag.Default, _
   ColorAdjustType.Bitmap)
      
e.Graphics.DrawImage(image, 10, 10, width, height)
      
' Pass in the destination rectangle (2nd argument), the upper-left corner 
' (3rd and 4th arguments), width (5th argument),  and height (6th 
' argument) of the source rectangle.
e.Graphics.DrawImage( _
   image, _
   New Rectangle(150, 10, width, height), _
   0, 0, _
   width, _
   height, _
   GraphicsUnit.Pixel, _
   imageAttributes)
[C#]
Image image = new Bitmap("ColorBars.bmp");
ImageAttributes imageAttributes = new ImageAttributes();
int width = image.Width;
int height = image.Height;

float[][] colorMatrixElements = { 
   new float[] {1,  0,  0,  0, 0},
   new float[] {0,  1,  0,  0, 0},
   new float[] {0.5f,  0,  1,  0, 0},
   new float[] {0,  0,  0,  1, 0},
   new float[] {0, 0, 0, 0, 1}};

ColorMatrix colorMatrix = new ColorMatrix(colorMatrixElements);

imageAttributes.SetColorMatrix(
   colorMatrix, 
   ColorMatrixFlag.Default,
   ColorAdjustType.Bitmap);

e.Graphics.DrawImage(image, 10, 10, width, height);

e.Graphics.DrawImage(
   image, 
   new Rectangle(150, 10, width, height),  // destination rectangle 
   0, 0,        // upper-left corner of source rectangle 
   width,       // width of source rectangle
   height,      // height of source rectangle
   GraphicsUnit.Pixel,
   imageAttributes);

下圖左邊顯示的是原始的影像，右邊顯示的是分歧的影像。

下列表格會列出分歧變換前後四列的色彩向量。

原始的	分歧的
(0, 0, 1, 1)	(0.5, 0, 1, 1)
(0.5, 1, 0.5, 1)	(0.75, 1, 0.5, 1)
(1, 1, 0, 1)	(1, 1, 0, 1)
(0.4, 0.4, 0.4, 1)	(0.6, 0.4, 0.4, 1)