如何扭曲图像以任何四边形？ [英] How to distort an image to any quadrangle?

问题描述

做任何你有一个想法，如何歪曲任何四边形的形象呢？ 我想实现的图像，你可以拉任何一个角落的任何方向，扭曲的图像。任何人有一个想法如何做到这一点？我用现在写的东西，在Android的一段时间，但它似乎并不像Android有一个函数，该函数。我真的不觉得自己写一个新的数学库。）

Do any of you have an idea, how to distort an image in any quadrangle? I want to implement an image, which you can pull any corner in any direction, distorting the image. Anyone has an idea how to do that? I use and write stuff in android for a while now, but it does not seem like android has a function for that. I don't really feel like writing a new math library :).

问候， 能否

推荐答案

<打击>看起来像你需要 Canvas.drawBitmapMesh 。有一个在Android SDK中的示例展示如何使用它。

Looks like you need Canvas.drawBitmapMesh . There is a sample in Android SDK showing how to use it.

您需要使用矩阵有关画布绘制位图。您可以轻松地创建一个适合你的位图图像与 Matrix.polyToPoly 的方法，任何四合院这样的转变。它看起来是这样的：

You need to use Matrix for drawing your bitmap on Canvas. You can easily create such transformation which will fit your bitmap image into any quadrangle with Matrix.polyToPoly method. It will look like this:

matrix.setPolyToPoly(
        new float[] { 
            0, 0, 
            bitmap.getWidth(), 0
            0, bitmap.getHeight(),
            bitmap.getWidth(), bitmap.getHeight() 
        }, 0, 
        new float[] { 
            x0, y0, 
            x1, y1, 
            x2, y2,
            x3, y3
        }, 0, 
        4);

canvas.drawBitmap(bitmap, matrix, paint);

当X0-X3，Y0-Y3是你的四边形顶点坐标。

Where x0-x3, y0-y3 are your quadrangle vertex coordinates.

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