Halftone effect in with gdi+

问题

How would I go about mimicking this halftone effect in GDI+?

It almost looks like Floyd–Steinberg dithered version of the image overlaying a full one but I'm not convinced.

回答1:

I gave this a try and got this result:

It may be a place to start. I did it like this:

Draw the original picture with low saturation (using a color matrix)
Draw the original image onto 1) with high saturation using a pattern mask (ie the dots)

I created the pattern mask like this:

        using (var g = Graphics.FromImage(bmpPattern))
        {
            g.Clear(Color.Black);
            g.SmoothingMode = SmoothingMode.HighQuality;
            for (var y = 0; y < bmp.Height; y += 10)
                for (var x = 0; x < bmp.Width ; x += 6)
                {
                    g.FillEllipse(Brushes.White, x, y, 4, 4);
                    g.FillEllipse(Brushes.White, x + 3, y + 5, 4, 4);
                }
        }

And then I imposed it over the oversaturated bitmap using this technique.

Update: Elaboration on how the images got merged. Let's talk even a little more general and say that we want to combine two different colorized versions of the same image using a pattern mask, resulting in a new image - we could do it like this:

Create THREE new bitmaps, all with the same size as the original image. Call them bmpA, bmpB and bmpMask.

Draw one colored/effect version into bmpA
Draw the other colored/effect version into bmpB
Create the mask in bmpMask (black and white)
Push one of the R/G/B channels of bmpMask into the alpha channel of bmpB using the transferOneARGBChannelFromOneBitmapToAnother method.
Draw bmpB over bmpA (since bmpB now has transparent parts in it)
The result is now bmpA. bmpB and bmpMask can be disposed.

Done

来源：https://stackoverflow.com/questions/8882512/halftone-effect-in-with-gdi

标签

gdi+