.NET Bitmap's Graphics.DrawString() // HDC ExtTExtout issues

[Lloyd Dupont]

In my .NET application I have some text rendered through GDI.
It draws and print nicely.

Now I would like to implement image export.
So I create a
new System.Drawing.Bitmap(width, height)
then I create a Graphic g = Graphics.FromImage(bmp)
then I use
HDC hdc = g.GetHdc();
and use ExtTextOut ....

problem is the output is horrible!
in fact even g.DrawString() has an horrible output.. (ultra heavy/bold
characters, so much so that's almost unreadable...)

With the HDC if I CreateFont(......, ANTIALIASED_QUALITY, ...) I have
something which is better but on the screen I better use CreateFont(......,
CLEARTYPE_QUALITY, ...)

How come output on the Bitmap is so bad?
Any tips?

 

[Kellie Fitton]

Hi,

You can use the following GDI+ methods to improve the output:

Graphics::SetInterpolationMode

Graphics::SetSmoothingMode

Graphics::SetPixelOffsetMode

http://msdn.microsoft.com/library/d...lass/GraphicsMethods/SetInterpolationMode.asp

http://msdn.microsoft.com/library/d...icsclass/graphicsmethods/setsmoothingmode.asp

http://msdn.microsoft.com/library/d...sClass/GraphicsMethods/SetPixelOffsetMode.asp

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdicpp/gdiplus/gdiplus.asp

http://msdn.microsoft.com/library/d...s/gdicpp/gdiplus/gdiplusreference/flatapi.asp

Hope these suggestions helps,

Kellie.

 

[Ben Voigt]

In my .NET application I have some text rendered through GDI.
It draws and print nicely.

Now I would like to implement image export.
So I create a
new System.Drawing.Bitmap(width, height)
then I create a Graphic g = Graphics.FromImage(bmp)
then I use
HDC hdc = g.GetHdc();
and use ExtTextOut ....

problem is the output is horrible!
in fact even g.DrawString() has an horrible output.. (ultra heavy/bold
characters, so much so that's almost unreadable...)

With the HDC if I CreateFont(......, ANTIALIASED_QUALITY, ...) I have
something which is better but on the screen I better use
CreateFont(......, CLEARTYPE_QUALITY, ...)

I suspect your image export is losing the alpha channel, so all your
partially transparent pixels on the edges of the text are becoming solid.

You might try filling in the image with an opaque background first so you
get blending and no transparency.