can gdip save as ".ico"?

[hyaray]

GdipSaveImageToFile seems not support the filetype... is there any other method to do this? thanks very much!!!

[iseahound]

Can you provide some working GDI+ code? I will investigate.

On Sat, Nov 5, 2022 at 11:30 hyaray @.***> wrote:

GdipSaveImageToFile seems to support the filetype... is there any other method to do this? thanks very much!!!

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[hyaray]

sorry, I think GdipSaveImageToFile may not able to do this. I'm tring python instead.

import os,sys
from PIL import Image

fp0 = r"c:\1.png"
fp1 = os.path.splitext(fp0)[0] + ".ico"
size = (16,16)
im = Image.open(fp0).resize(size)
im.save(fp1)

[iseahound]

Depending on your use case, you can actually change the *.png extension to *.ico, and it should work.

[iseahound]

Just a little update: This needs some more investigation. In general, an *.ico file contains about 9 resolutions. These are mostly encoded as a bitmap and stored sequentially.

So something like generating:

• 16 x 16
• 64 * 64
• 256 x 256 could be done automatically. I should also allow passing an array of sizes as well.

Here's the interesting part: An ICO file can host embedded PNGs. Since the IconDirEntry header uses a UCHAR for storage of width and height, the maximum width and height is 256 x 256 which is the maximum value for an unsigned char (one byte). But it will recognize one special PNG with an icon size of 256 x 256 and will use the width and height embedded inside the PNG instead. So theoretically, the size limit inside an ICO can be bigger than 256 x 256.