Trying to add transparent text with TextRenderer.DrawText to a bitmap image

Question

I'm actually trying to add some text to an image in C# with

System.Windows.Forms.TextRenderer.DrawText(Graphics, string, Rectangle, Color, TextFormaFlags)

I prepare my image (which is a png) by loading it in memory, with something similar to

Image image = ImageCache.Get(...); bitmap = new Bitmap(image); graphic = Graphics.FromImage(bitmap);

I then draw my text with the above command. The problem is that whatever I use for the color, even something like

System.Drawing.Color.FromArgb(0,255,255,255)

the transparency is not drawn. I tried many settings for

graphics.TextRenderingHint

and different combinations of fonts, transparency level, etc. Is there something I don't understand here? Any hint is appreciated.

Thank you.

Use Color.Transparent as BackColor or use Graphics.DrawString. See: TextRenderer.DrawText in Bitmap vs OnPaintBackground — Olivier Jacot-Descombes
– Olivier Jacot-Descombes, Commented Feb 9, 2016 at 20:57
If you want alpha blending effects then you must use Graphics.DrawString(), TextRenderer uses GDI which is limited to RGB. — Hans Passant
– Hans Passant, Commented Feb 9, 2016 at 21:11
@Hans Passant Well, not the answer I wanted to hear, but good to know. If you put it as a formal answer, I'll accept it. — Bene Tleilax
– Bene Tleilax, Commented Feb 9, 2016 at 21:18
I avoid posting answers that nobody wants to hear. You can post it yourself and accept it. — Hans Passant
– Hans Passant, Commented Feb 9, 2016 at 21:20

Bene Tleilax · Accepted Answer · 2016-02-10 14:36:46Z

As mentionned in the comments : if you try to draw transparent text with

System.Windows.Forms.TextRenderer.DrawText

because you look for the advantages brought by GDI in C#, you just can't. Use

System.Drawing.Graphics.DrawString

instead, even if the result for the word-wrapping is slightly inferior with GDI+.

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