GDI color depth?

[RobT]

I'll admit, that I don't do a lot of GDI+ programming and I'm sure this is
an easy answer. I'm trying to draw a couple of shapes in a web site. I can
display them just fine, but on some of the fill colors are pixelated. Is
there a way to render these colors at a better color depth?

Dim bmp As Bitmap
bmp = New Bitmap(200, 200)
Dim g As Graphics
g = Graphics.FromImage(bmp)
g.Clear(Color.White)
g.SmoothingMode = SmoothingMode.AntiAlias
Dim brsh As SolidBrush
brsh = New SolidBrush(Color.DarkGoldenrod)
g.FillPie(brsh, 10, 10, 50, 50, 0, 360)

Thanks

 

[Herfried K. Wagner [MVP]]

I'll admit, that I don't do a lot of GDI+ programming and I'm sure this is
an easy answer. I'm trying to draw a couple of shapes in a web site. I
can display them just fine, but on some of the fill colors are pixelated.
Is there a way to render these colors at a better color depth?

Dim bmp As Bitmap
bmp = New Bitmap(200, 200)
Dim g As Graphics
g = Graphics.FromImage(bmp)
g.Clear(Color.White)
g.SmoothingMode = SmoothingMode.AntiAlias
Dim brsh As SolidBrush
brsh = New SolidBrush(Color.DarkGoldenrod)
g.FillPie(brsh, 10, 10, 50, 50, 0, 360)

Take a look at the different constructors of the 'Bitmap' class. In
addition, take a look at the different overloads of the 'Save' method. Note
that some image formats, such as GIF, only support a certain number of
colors in the image making dithering necessary.

 

[RobT]

Thanks for the pointers. I did modify the Save method to be jpeg instead
and that helps.

bmp.Save(Response.OutputStream, ImageFormat.Jpeg)

Now, is there a way to reduce the amount of compression of the jpeg so the
image is sharper? I(I have some other lines, text etc in my output). The
antialias looks fine...I'm pretty sure the compression is too high.

Thanks!

 

[Armin Zingler]

Now, is there a way to reduce the amount of compression of the jpeg so the
image is sharper? I(I have some other lines, text etc in my output).
The antialias looks fine...I'm pretty sure the compression is too high.

http://msdn.microsoft.com/en-us/library/bb882583.aspx


Armin

 

[RobT]

Thanks....I just discovered that myself! Works great.

 

[Andrew Morton]

Thanks for the pointers. I did modify the Save method to be jpeg
instead and that helps.

bmp.Save(Response.OutputStream, ImageFormat.Jpeg)

Now, is there a way to reduce the amount of compression of the jpeg
so the image is sharper? I(I have some other lines, text etc in my
output). The antialias looks fine...I'm pretty sure the compression
is too high.

Depending on your target audience, png could be a suitable file format.

Andrew