/// <summary>
/// Renders a test image.
/// </summary>
/// <param name="width">Width of the test image.</param>
/// <param name="height">Height of the test image.</param>
/// <param name="blockSize">Block size used for coloring the test image.</param>
/// <param name="tileX">The x-coordinate of the tile being requested; used for dynamically coloring the image.</param>
/// <param name="tileY">The y-coordinate of the tile being requested; used for dynamically coloring the image.</param>
/// <returns></returns>
protected virtual Image RenderTestImage(int width, int height, int?blockSize, int tileX, int tileY)
{
// correct block size
if (blockSize.GetValueOrDefault(0) < 8)
{
blockSize = Math.Max(width, height);
}
// set of colors we're working with
var colors = new[] { Color.Red, Color.Blue, Color.Green, Color.Cyan, Color.Violet, Color.Yellow };
// determine colors to be used,
// set up reduced color set
const int mod = 64;
var color0 = colors[(tileX + tileY) % colors.Length];
var color1 = Color.FromArgb(255, Math.Max(0, color0.R - mod), Math.Max(0, color0.G - mod), Math.Max(0, color0.B - mod));
var color2 = Color.FromArgb(255, Math.Min(255, color0.R + mod), Math.Min(255, color0.G + mod), Math.Min(255, color0.B + mod));
colors = new[] { color1, color2 };
Func <int, int> nextColor = index => (index + 1) % colors.Length;
var colorStart = 0;
var colorIndex = 0;
// create resulting image
var bmp = new Bitmap(width, height);
// get graphics object for drawing into the image
using (var g = Graphics.FromImage(bmp))
// loop through blocks
if (blockSize != null)
{
foreach (var block in BlockBuilder.GetBlocks(width, height, blockSize.Value))
{
// BlockBuilder.GetBlocks returns blocks column-wise
// so we use block.y0 == 0 to trigger a color swap
if (block.Y0 == 0)
{
colorStart = nextColor(colorIndex = colorStart);
}
// render current block
g.FillRectangle(new SolidBrush(colors[colorIndex]), block.X0, block.Y0, block.X1 - block.X0 + 1,
block.Y1 - block.Y0 + 1);
// next block > next color
colorIndex = nextColor(colorIndex);
}
}
// return image
return(bmp);
}