Question

我正试图与全球移民与发展公司一道执行从C++的平时起的梯度。我不想使用全球发展指数+或任何其他图表框架。我想梯度方向(任意角)。

我在假体编码中的算法:

      For each pixel in x dirrection
      For each pixel in the y direction
          current position = current pixel - centre                      //translate origin 
          rotate this pixel according to the given angle
          scalingFactor =( rotated pixel + centre ) / extentDistance    //translate origin back 
          rgbColor = startColor + scalingFactor(endColor - startColor)

范围距离是指从试金星中心穿过线的长度,梯度等于梯度的角。

Ok so far so good. I can draw this and it looks nice. BUT unfortunately because of the rotation bit the rectangle corners have the wrong color. The result is perfect only for angle which are multiples of 90 degrees. The problem appears to be that the scaling factor doesn t scale over the entire size of the rectangle.

我不敢肯定,如果你不视而不谈我的问题,那真是难以解释。

If anyone can help or redirect me to some helpful material I d be grateful.

Answer 1

Ok guys fixed it. Apparently the problem was that when I was rotating the gradient fill (not the rectangle) I wasn t calculating the scaling factor correctly. The distance over which the gradient is scaled changes according to the gradient direction. What must be done is to find where the edge points of the rect end up after the rotation and based on that you can find the distance over which the gradient should be scaled. So basically what needs to be corrected in my algorithm is the extentDistance.

How to do it:

•Transform the coordinates of all four corners

• 占全部四分之十的最小

• 占全部四×中的最大部分,称为最高点X

• ......

• 这两点之间的距离(最大和最小)是程度差异

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