8-bit graphic formats

[wolfgang]

Hi,
when I try to load an 8-bit graphic format (gif or bmp), I get the attached error message (PC). This happens only, when I want to draw with drawer.New2 (ImageList1.Item (0), B4PObject (5)) on this image. No problems with 24-bit formats.

[Erel]

Can you upload this bitmap file?

[wolfgang]

Hi Erel,
here it is. It's 8-bit bmp with 256 colors.

[agraham]

It seems there is a GDI+ Graphics limitation - From MSDN

"Note You can only create Graphics objects from non-indexed .bmp files, such as 16-bit, 24-bit, and 32-bit .bmp files. Each pixel of non-indexed .bmp files holds a color, in contrast to pixels of indexed .bmp files, which hold an index to a color table."

[wolfgang]

That's exactly what the error message says. And it's the same with a gif file.

[klaus]

Hi wolfgang
How do you load your image ?
In my program to display maps I load the image files in an ImageList object, and I had no problem loading your image.
You can look at it in:
http://www.basic4ppc.com/forum/share-your-creations/1612-display-maps.html

Best regards
Klaus
Switzerland

[Erel]

A fix for this limitation is to create a copy of the image:

    image1.Visible = false
image1.Image = "b.bmp"
image1.Image = image1.Image 'creates a nonindexed copy of the image.
drawer.New2(image1.Image,B4PObject(5))

[wolfgang]

Hi,
thank you all. The good news: This happens only on desktop. On PPC is no error.

The problem is not, that I can’t do this.The problem was that I want to save memory on PPC. But I found, that it doesn’t matter if you load the same file as a bmp (24-bit), jpg or a gif. In comparison to the desktop where the gif files are much smaller in RAM. On my device (ASUS 632N WM5) a 6 MB bmp or the same file as an 800 KB gif takes about 4 MB of memory(?!). But there is still a difference: bmp files can be loaded up to a size of ~ 1700 x 1700 pixels and gif files much bigger e.g. 2400 x 1800 pixels. I didn’t test the maximum.

@Klaus
wonderful software. But you don’t draw on your maps. Add an object named draw and this line of code:

.
.
.
draw.New2 (ImageList1.Item (Map_I), B4PObject (5))

and you will get the same error message. I tested it. Again: wonderfull software.

[klaus]

Hi wolfgang,
You are right, if I add a drawer connected to the 8bit image I get the same error message.

Klaus
Switzerland

[agraham]

Originally Posted by wolfgang

The problem was that I want to save memory on PPC. But I found, that it doesn’t matter if you load the same file as a bmp (24-bit), jpg or a gif.

I'm afraid you can't save memory just by loading a different format. Jpg and gif are compressed formats for storing pictures in files. However pictures are always expanded to full bitmaps when loaded into memory no matter what the format of the source file.