/// <summary>
/// Renders a pixelated version of <see cref="originalImage"/>. If <paramref name="renderGrid"/> is true, a grid will be drawn over the image.
/// </summary>
/// <param name="renderGrid"></param>
/// <returns>The pixelated version of the image.</returns>
private Image RenderImage(bool renderGrid = true)
{
if (originalImage as Bitmap == null)
{
return(null);
}
Bitmap source = originalImage as Bitmap;
Bitmap rasterized = new Bitmap(originalImage.Width, originalImage.Height);
int gridSize = tbGridSize.Value;
//Well keep a list of rectangles per color, so we can show the usage count of each color,
//but this also enables us to draw all rectangles of the same color in one operation.
drawList = new Dictionary <Color, List <Rectangle> >();
for (int x = 0; x < rasterized.Width; x += gridSize)
{
for (int y = 0; y < rasterized.Height; y += gridSize)
{
int width = gridSize, height = gridSize;
//Fix width or height if the image is not divided in squares (near the edges)
if (x + gridSize >= rasterized.Width)
{
width = (rasterized.Width) - x - 1;
}
if (y + gridSize >= rasterized.Height)
{
height = (rasterized.Height) - y - 1;
}
Rectangle block = new Rectangle(x, y, width, height);
Color pixel = interpolator.DetermineColor(source, block);
if (!drawList.ContainsKey(pixel))
{
drawList.Add(pixel, new List <Rectangle>());
}
drawList[pixel].Add(block);
}
}
using (Graphics g = Graphics.FromImage(rasterized)) {
//Using each color, draw the list of rectangles at once
foreach (Color key in drawList.Keys)
{
using (Brush b = new SolidBrush(key))
g.FillRectangles(b, drawList[key].ToArray());
}
if (renderGrid)
{
//Draw horizontal lines
for (int x = gridSize; x < rasterized.Width; x += gridSize)
{
g.DrawLine(Pens.Black, x, 0, x, rasterized.Height);
}
//Draw vertical lines
for (int y = gridSize; y < rasterized.Height; y += gridSize)
{
g.DrawLine(Pens.Black, 0, y, rasterized.Width, y);
}
}
}
return(rasterized);
}