Search found 8 matches

by VTT
2015-11-27T01:16:29-07:00
Forum: Users
Topic: Save Bitmap as bmp3 preserving alpha channel.
Replies: 16
Views: 11239

Re: Save Bitmap as bmp3 preserving alpha channel.

Alright, thank you.
by VTT
2015-11-26T02:18:58-07:00
Forum: Users
Topic: Save Bitmap as bmp3 preserving alpha channel.
Replies: 16
Views: 11239

Re: Save Bitmap as bmp3 preserving alpha channel.

I 'm not really familiar with command style in IM, is there a reason why explicit

Code: Select all

-depth 32
is not going to work?
by VTT
2015-11-25T12:06:02-07:00
Forum: Users
Topic: Save Bitmap as bmp3 preserving alpha channel.
Replies: 16
Views: 11239

Re: Save Bitmap as bmp3 preserving alpha channel.

This image seem to have monochrome alpha (either 0 or 255) but is fine otherwise.

I admit that it is not fully supported and some applications tend to ignore saved alpha, but it works good as a resource file.
by VTT
2015-11-25T01:06:32-07:00
Forum: Users
Topic: Save Bitmap as bmp3 preserving alpha channel.
Replies: 16
Views: 11239

Re: Save Bitmap as bmp3 preserving alpha channel.

BMP3 which is BITMAPFILEHEADER + BITMAPINFOHEADER can hold alpha channel, biBitCount need to be 32 and biCompression BI_RGB as stated here.
by VTT
2015-11-24T23:40:27-07:00
Forum: Users
Topic: Save Bitmap as bmp3 preserving alpha channel.
Replies: 16
Views: 11239

Re: Save Bitmap as bmp3 preserving alpha channel.

MSDN page states that
Alpha values per pixel are only supported for 32-bpp BI_RGB.
Anyway, v3 bitmaps with alpha are used everywhere.
by VTT
2015-11-24T14:59:43-07:00
Forum: Users
Topic: Save Bitmap as bmp3 preserving alpha channel.
Replies: 16
Views: 11239

Re: Save as Bitmap v4 (bmp3) preserving alpha channel.

It seems to be a bug since imagemagick correctly saves alpha in BMP4 while BMP3 definitely does allow transparency or at least 32 bpp (exactly as BMP4). And it is actually stated later on that page: For comparison, the bmp3: format allows bit depths of 0, 1, 4, 8 ,16, 24 and 32 and has extra fields ...
by VTT
2015-11-24T13:59:23-07:00
Forum: Users
Topic: Save Bitmap as bmp3 preserving alpha channel.
Replies: 16
Views: 11239

Re: Save as Bitmap v4 (bmp3) preserving alpha channel.

fmw42 wrote:For your output use BMP3:output.bmp
this approach gives me exactly the same bitmap as -define bmp:format=bmp3
by VTT
2015-11-24T13:43:00-07:00
Forum: Users
Topic: Save Bitmap as bmp3 preserving alpha channel.
Replies: 16
Views: 11239

Save Bitmap as bmp3 preserving alpha channel.

I'm trying to convert pngs into bitmaps with premultiplied alpha to be used as Portable Executable resources with Power Shell script: $converter = "`"C:\Program Files\Image Magick\convert.exe`"" foreach($file_path in $args) { $file_name = $file_path.substring(0, ($file_path.length - 4)) $command = "...