描述

 

用自身和另一个矩阵的乘积更新画笔的变换矩阵.

 

C++ Syntax

 

 

FreeBASIC 语法

 

 

参数

 

pMatrix

 

[in]指向矩阵乘以刷的电流变换矩阵.

 

order

 

该MatrixOrder指定相乘的顺序[in, optional]元.MatrixOrderPrepend指定传递矩阵是在左边,和MatrixOrderAppend指定传递矩阵是正确的.默认值是MatrixOrderPrepend.

 

返回值

 

如果该方法成功,则返回Ok,这是对Status枚举元素.

如果这个方法失败,它返回一个枚举的其他元素的Status.

 

备注

 

一个3？矩阵可以存储任意序列的仿射变换.如果你有几个3？矩阵,其中每一个表示仿射变换,这些矩阵的产品是一个单一的3？表示整个变换序列的矩阵.该产品表示的变换称为复合变换.例如,假设矩阵R代表一个旋转矩阵T代表翻译.如果矩阵M是产品RT,然后矩阵M代表复合变换：先旋转,然后翻译.

矩阵乘法的顺序是重要的.在一般情况下,矩阵的乘积RT不是矩阵的乘积TR相同.在上一段中给出的例子中,由RT复合变换（旋转,然后翻译）不为代表的TR复合变换相同（第一次翻译,然后旋转）.

 

引用文件

 

CGpBrush.inc (include CGdiPlus.inc)

 

示例

 

' ========================================================================================

' The following example creates a PathGradientBrush object based on a triangular path. The

' code calls the PathGradientBrush.ScaleTransform method of the PathGradientBrush object

' to fill the brush's transformation matrix with the elements that represent a horizontal

' scaling by a factor of 3. Then the code calls the PathGradientBrush.MultiplyTransform

' method of that same PathGradientBrush object to multiply the brush's existing transformation

' matrix by a matrix that represents a translation (10 right, 30 down). The MatrixOrderAppend

' argument indicates that the multiplication is performed with the translation matrix on the right.

' After the multiplication, the brush's transformation matrix represents a composite

' transformation: first scale, then translate. That composite transformation is applied to

' the brush's boundary path during the call to FillRectangle, so it is the area inside the

' transformed path that gets painted.

' ========================================================================================

SUB Example_MultiplyTransform (BYVAL hdc AS HDC)

 

  ' // Create a graphics object from the window device context

  DIM graphics AS CGpGraphics = hdc

  ' // Get the DPI scaling ratio

  DIM rxRatio AS SINGLE = graphics.GetDpiX / 96

  DIM ryRatio AS SINGLE = graphics.GetDpiY / 96

  ' // Set the scale transform

  graphics.ScaleTransform(rxRatio, ryRatio)

 

  DIM points(0 TO 2) AS GpPoint = {GDIP_POINT(0, 0), GDIP_POINT(50, 0), GDIP_POINT(50, 50)}

 

  ' // Translate 10 right, 30 down.

  DIM Matrix AS CGpMatrix = CGpMatrix(1.0, 0.0, 0.0, 1.0, 10.0, 30.0)

 

  DIM pthGrBrush AS CGpPathGradientBrush = CGpPathGradientBrush(@points(0), 3)

  pthGrBrush.ScaleTransform(3.0, 1.0)

  pthGrBrush.MultiplyTransform(@matrix, MatrixOrderAppend)

 

  graphics.FillRectangle(@pthGrBrush, 0, 0, 200, 200)

 

END SUB

' ========================================================================================