Question

我正试图在Android中对BitMap图像实现鱼眼效果。是否有现有的库或算法可以提供帮助？

Answer 1

我建议您使用Android Media Effects API。如果您想要更好地控制效果（或定位较旧的Android版本），您还可以直接使用opengl为您的照片应用鱼眼效果。关于这个主题的一些教程：http://www.learnopengles.com/android-lesson-four-introducing-basic-texturing/。学习opengl将允许您对照片应用所有类型的效果，可以在互联网上轻松找到着色器代码（例如：https://github.com/BradLarson/GPUImage/tree/master/framework/Source）

以下是鱼眼效果的着色器代码：

private static final String FISHEYE_FRAGMENT_SHADER =
        "precision mediump float;\n" +
        "uniform sampler2D u_Texture;\n" +
        "uniform vec2 vScale;\n" +
        "const float alpha = float(4.0 * 2.0 + 0.75);\n" +
        "varying vec2 v_TexCoordinate;\n" +
        "void main() {\n" +
        "  float bound2 = 0.25 * (vScale.x * vScale.x + vScale.y * vScale.y);\n" + 
        "  float bound = sqrt(bound2);\n" +
        "  float radius = 1.15 * bound;\n" +
        "  float radius2 = radius * radius;\n" +
        "  float max_radian = 0.5 * 3.14159265 - atan(alpha / bound * sqrt(radius2 - bound2));\n" + 
        "  float factor = bound / max_radian;\n" + 
        "  float m_pi_2 = 1.570963;\n" +
        "  vec2 coord = v_TexCoordinate - vec2(0.5, 0.5);\n" +
        "  float dist = length(coord * vScale);\n" +
        "  float radian = m_pi_2 - atan(alpha * sqrt(radius2 - dist * dist), dist);\n" +
        "  float scalar = radian * factor / dist;\n" +
        "  vec2 new_coord = coord * scalar + vec2(0.5, 0.5);\n" +
        "  gl_FragColor = texture2D(u_Texture, new_coord);\n" +
        "}\n";

Answer 2

了解OpenCV for Android：

http://opencv.org/platforms/android.html

这个回答：

How to simulate fisheye lens effect by openCV?

Answer 3

也许更简单的解决方案是使用Android Media Effects API。但它仅适用于API 14及更高版本。

如何在Android中实现鱼眼效果？

3 个答案: