private unsafe void generate_alpha_mask(int cx, int cy)
{
alphaByteArray = new byte[cx * cy];
{
#if USE_CLIPPING_ALPHA_MASK
alphaMaskImageBuffer.AttachBuffer(alphaByteArray, 20 * cx + 20, cx - 40, cy - 40, cx, 8, 1);
#else
alphaMaskImageBuffer.attach(alphaByteArray, (int)cx, (int)cy, cx, 1);
#endif
ImageBuffer image = new ImageBuffer();
image.Attach(alphaMaskImageBuffer, new blender_gray(1), 1, 0, 8);
ImageClippingProxy clippingProxy = new ImageClippingProxy(image);
ScanlineCachePacked8 sl = new ScanlineCachePacked8();
clippingProxy.clear(new ColorF(0));
VertexSource.Ellipse ellipseForMask = new MatterHackers.Agg.VertexSource.Ellipse();
System.Random randGenerator = new Random(1432);
ScanlineRenderer scanlineRenderer = new ScanlineRenderer();
int i;
int num = (int)numMasksSlider.Value;
for (i = 0; i < num; i++)
{
if (i == num - 1)
{
ellipseForMask.init(Width / 2, Height / 2, 110, 110, 100);
rasterizer.add_path(ellipseForMask);
scanlineRenderer.RenderSolid(clippingProxy, rasterizer, sl, new Color(0, 0, 0, 255));
ellipseForMask.init(ellipseForMask.originX, ellipseForMask.originY, ellipseForMask.radiusX - 10, ellipseForMask.radiusY - 10, 100);
rasterizer.add_path(ellipseForMask);
scanlineRenderer.RenderSolid(clippingProxy, rasterizer, sl, new Color(255, 0, 0, 255));
}
else
{
ellipseForMask.init(randGenerator.Next() % cx,
randGenerator.Next() % cy,
randGenerator.Next() % 100 + 20,
randGenerator.Next() % 100 + 20,
100);
// set the color to draw into the alpha channel.
// there is not very much reason to set the alpha as you will get the amount of
// transparency based on the color you draw. (you might want some type of different edeg effect but it will be minor).
rasterizer.add_path(ellipseForMask);
scanlineRenderer.RenderSolid(clippingProxy, rasterizer, sl, new Color((int)((float)i / (float)num * 255), 0, 0, 255));
}
}
alphaMaskImageBuffer.DettachBuffer();
}
}
