如何创建一个具有扭曲效果的NSAffineTransform？ [英] How do I create an NSAffineTransform with a skew effect?

问题描述

我很喜欢在Cocoa中绘画，并在一个涉及六角网格的实验性应用上工作。为了简化这一点，我想倾斜坐标系，使Y轴向左旋转30度。我在Apple的可可绘图指南，这表明它是可能的：

结合非均匀缩放变换和旋转变换也可能会导致内容偏斜效果。

然而，我无法理解这将如何工作，或找到任何示例。

如何设置NSAffineTransform，使X轴保持水平，Y轴逆时针旋转30度？ 解决方案不幸的是，有没有简单的方法来做到这一点，就像变换，旋转等一样。

您必须创建一个变换矩阵：

p>

  0 tan（skewy）0 
 tan（skewx）0 0 
 0 0 1 
  

使用 setTransformStruct：与 NSAffineTransformStruct ：

  typedef struct _NSAffineTransformStruct {
 CGFloat m11，m12，m21，m22; 
 CGFloat tX，tY; 
} NSAffineTransformStruct; 
  

对于偏斜，m11，m22，tx和ty为零; m12是tan（skewx），m21是tan（skewy）

Apple的文档中有更多关于矩阵的信息： https：/ /developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/CocoaDrawingGuide/Transforms/Transforms.html#//apple_ref/doc/uid/TP40003290-CH204-BCIIICJI

希望这有助于！

I'm quite new to drawing in Cocoa, and working on an experimental app involving a hexagonal grid. In order to simplify this, I want to skew the coordinate system so that the Y axis is rotated 30 degrees to the left. I came across this in Apple's Cocoa Drawing Guide, which indicates it is possible:

Combining a non-uniform scaling transform with a rotation transform can also give your content a skewed effect.

However, I cannot understand how this would work, or locate any examples.

How can I set up an NSAffineTransform so that the X axis remains horizontal and the Y axis is rotated counteclockwise by 30 degrees?

解决方案

Unfortunately, there is no easy way to do this as you would with transforms, rotations, etc.

You have to create a transform matrix:

0            tan(skewy)   0
tan(skewx)   0            0
0            0            1

Using setTransformStruct: with an NSAffineTransformStruct:

typedef struct _NSAffineTransformStruct {
  CGFloat m11, m12, m21, m22;
  CGFloat tX, tY;
} NSAffineTransformStruct;

For skewing, m11, m22, tx, and ty are zero; m12 is tan(skewx) and m21 is tan(skewy)

There is much more information on matrices in Apple's documentation: https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/CocoaDrawingGuide/Transforms/Transforms.html#//apple_ref/doc/uid/TP40003290-CH204-BCIIICJI

Hope this helps!

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