C# Color an image with shadows

Question

I am currently creating sort of a game with C# and am trying to create outfits for the players. I would like to make cloth design and let players chose the colors.

I took pictures from gamefiles of TibiaME (tibiame.com), which does pretty much what i want to to.

How can I Fill this form with color? When I try to replace a certain color, it does not work, since it's not the same everyhwere. The shadows look pretty cool :P

To change hues use a color matrix. Or look at [this post](https://stackoverflow.com/questions/41777110/change-image-color-with-transparent-background/41781248#41781248) — TaW, Jul 25 '18 at 20:18
So what exactly are you using for the graphics? Are you using a game engine like Unity? An OpenGL library? System.Drawing? Without this info nobody's gonna be able to give you a C# specific answer. Just conceptual answers. BTW: System.Drawing is not hardware accelerated so if you start doing realtime pixel operations you will not be able to run at a high framerate. — Chris Rollins, Jul 25 '18 at 20:20

TaW · Accepted Answer · 2018-07-26T08:17:10.960

The simplest (and fastest) way to color (tint) an image is to use a ColorMatrix.

Here is the result of using nine colors to tint the original:

Note that I have photoshopped the posted image bo be transparent around the center part; using just the original looks like this..:

((The glitch in the lower right is in the original..))

Here is a function the returns a list of tinted version of an image, one for each color in a list..:

List<Bitmap> TintImages(Bitmap bmp0, List<Color> colors )
{
    List<Bitmap> tinted = new List<Bitmap>();
    Size sz = bmp0.Size;
    float f = 256f;
    for (int i = 0; i < colors.Count; i++)
    {
        float r = colors[i].R / f;
        float g = colors[i].G / f;
        float b = colors[i].B / f;

        float[][] colorMatrixElements = {
            new float[] {r,  0,  0,  0, 0},        // red scaling factor of 
            new float[] {0,  g,  0,  0, 0},        // green scaling factor 
            new float[] {0,  0,  b,  0, 0},        // blue scaling factor 
            new float[] {0,  0,  0,  1, 0},        // alpha scaling factor 
            new float[] {0, 0, 0, 0, 1}};          // no further translations
        ImageAttributes imageAttributes = new ImageAttributes();
        ColorMatrix colorMatrix = new ColorMatrix(colorMatrixElements);
        imageAttributes.SetColorMatrix(
            colorMatrix,
            ColorMatrixFlag.Default,
            ColorAdjustType.Bitmap);
        Bitmap bmp = new Bitmap(sz.Width, sz.Height);
        using (Graphics gr = Graphics.FromImage(bmp))
        {
            gr.DrawImage(bmp0, new Rectangle(0, 0, sz.Width, sz.Height),
            0, 0, sz.Width, sz.Height, GraphicsUnit.Pixel, imageAttributes);
            tinted.Add(bmp);
        }
    }
    return tinted;
}

RomCoo · Answer 2 · 2018-07-25T20:48:40.710

You could iterate over each pixel of the bitmap and make a color shift in the direction you want. When I say colorshoft I mean a you have to adapt the RGB values of each pixel.

A simple shift to red could look like this:

for (int Xcount = 0; Xcount < myBitmap.Width; Xcount++)
{
    for (int Ycount = 0; Ycount < myBitmap.Height; Ycount++)
    {
        //get color of the pixel
        Color pixelColor = myBitmap.GetPixel(Xcount, Ycount);
        byte red = pixelColor.R;
        byte green = pixelColor.G;
        byte blue = pixelColor.B;

        //make shift and prevent overflow
        if (red < 205)
            red += 50;
        else
            red = 255;

        //set color of the pixel
        myBitmap.SetPixel(Xcount, Ycount, Color.FromRgb(red, green, blue));
    }
}

Keep in mind this is just a simple example and may not result in what you expected. You can read more about the RGB colorspace here: RGB color model and here you find a RGB Color Codes Chart

C# Color an image with shadows

2 Answers2

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