Re: About GD Image Data Output Methods

Karl, try using this to convert the internal gd format to a Windows .BMP format. After that, any of your image converters should be able to port it to whatever format you require.

# ... $image is your GD::Image for output

my $gd = $image->gd;
my @attrs = unpack 'nnnCV', substr( $gd, 0, 11, '' );
my $len = length( $gd ) / 4 * 3;
my $bmp = pack 'a2 V V V l< l< l< v v V V l< l< V V',
    'BM', $len + 54, 0, 54, 40, $attrs[1], $attrs[2], 1, 24, $len, 0, 
+0, 0, 0;

$bmp .= join'', unpack '(xaaa)*', $gd;

## Now print $bmp to a file xxx.bmp and convert; or maybe pipe directl
+y to an image converter for conversion.
[download]

It's a bit "magic number" ladened, but that's all they are; magic numbers.

Yell, if you really need the explanation :)

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority". I'm with torvalds on this

In the absence of evidence, opinion is indistinguishable from prejudice. Agile (and TDD) debunked

Comment on Re: About GD Image Data Output Methods Download Code

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Re^2: About GD Image Data Output Methods by karlgoethebier (Abbot) on Jun 07, 2015 at 19:01 UTC
Pure magic, especially this line: `my $bmp = pack 'a2 V V V l< l< l< v v V V l< l< V V', 'BM', $len + 54, 0, 54, 40, $attrs[1], $attrs[2], 1, 24, $len, 0, +0, 0, 0;` [download] I tried it immediately but i can't view the file with various image processing software. In some it is simply black, some other reject it. Examining the file i get: `karls-mac-mini:monks karl$ file mandelbrot.bmp mandelbrot.bmp: PC bitmap, Windows 3.x format, 1280 x 1024 x 24` [download] This looks good, but: karls-mac-mini:monks karl$ identify mandelbrot.bmp identify: unrecognized compression `mandelbrot.bmp'. [download] Or something is wrong with my GD installation. But i don't think so because the script would complain if something went wrong. Thank you very much for advice. Perhaps you have a hint how to continue. Best regards, Karl ŤThe Crux of the Biscuit is the Apostropheť	[reply] [d/l] [select]
Re^3: About GD Image Data Output Methods by BrowserUk (Patriarch) on Jun 07, 2015 at 19:33 UTC
Try this version: `my $gd = $image->gd; my( undef, $width, $height, undef, undef ) = unpack 'nnnCV', substr( $ +gd, 0, 11, '' ); my $len = length( $gd ) / 4 * 3; my $bmp = pack 'a2 V V V l< l< l< v v V V l< l< V V', 'BM', $len + 54, 0, 54, 40, $width, -$height, 1, 24, 0, $len, 0, 0 +, 0; $bmp .= join'', unpack '(xaaa)*', $gd;` [download] Looks like I had two fields transposed; even though my image viewer didn't notice (or just didn't look). With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". I'm with torvalds on this In the absence of evidence, opinion is indistinguishable from prejudice. Agile (and TDD) debunked	[reply] [d/l]
Re^4: About GD Image Data Output Methods by karlgoethebier (Abbot) on Jun 07, 2015 at 20:06 UTC
Now i get: identify: Insufficient image data in file `mandelbrot.bmp'. ŤThe Crux of the Biscuit is the Apostropheť	[reply] [d/l]
Re^5: About GD Image Data Output Methods by BrowserUk (Patriarch) on Jun 07, 2015 at 20:13 UTC
Re^6: About GD Image Data Output Methods by karlgoethebier (Abbot) on Jun 07, 2015 at 21:01 UTC
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