NAME

GD::Raw - Low level language bindings to GD Graphics Library

SYNOPSIS

use GD::Raw;

my $fh = fopen("my-image.png", "rb");
my $img = gdImageCreateFromPng($fh);
LEAVE gdImageDestroy($_) with $img;

say "Image resolution is ", gdImageSX($img), "x", gdImageSX($img);

DESCRIPTION

GD::Raw is a low level language bindings to LibGD. It does not attempt to provide you with an rakuish interface, but tries to stay as close to its C origin as possible.

LibGD is large and this module far from covers it all. Feel free to add anything your missing and submit a pull request!

FUNCTIONS PORTED TO RAKU

Not all libgd functions are ported to Raku module GD::Raw. Here is the list of these functions, in the same order as the libgd 2.3.3 documentation

Image Formats

gdImageBmpPtr

gdImageBmp

gdImageCreateFromBmp

gdImageCreateFromGif

gdImageCreateFromJpeg

gdImageCreateFromPng

`gd.c`

`gd.h`

Colour Decomposition

gdTrueColorGetAlpha

gdTrueColorGetRed

gdTrueColorGetGreen

gdTrueColorGetBlue

Color Composition

gdTrueColorAlpha

Accessor Macros

gdImageSX

gdImageSY

gdImageColorsTotal

[gdImageRed](https://libgd.github.io/manuals/2.3.3/files/gd-h.html#gdImageRed

L<C<gdImageGreen)|https://libgd.github.io/manuals/2.3.3/files/gd-h.html#gdImageGreen>

gdImageBlue

gdImageAlpha

`gd_interpolation.c`

gdImageScale

gdImageRotateInterpolated

gdImageSetInterpolationMethod

`gd_version.c`

gdFree

gdFree

Image Filters

gdImageSelectiveBlur

gdImageEdgeDetectQuick

gdImageGaussianBlur

gdImageEmboss

gdImageMeanRemoval

gdImageSmooth

gdImageCopyGaussianBlurred

Additional Functions

fopen file management for graphic files

fclose file management for graphic files

gdImageCreatePalette is an alias of gdImageCreate.

MEMORY MANAGEMENT

When creating an in-memory image, some memory is allocated in GD. This memory is not automatically deallocated when the variable which refers to the image goes out of scope. To counter this possible memory leak, the simplest way is to use the LEAVE phaser and call function gdImageDestroy like this

my $img = gdImageCreateFromPng($fh);
LEAVE gdImageDestroy($_) with $img;

If a program creates several images, there will be a problem if the program reuses the $img variable. In this case, you cannot use the LEAVE phaser, you must call gdImageDestroy before creating the second image (and the third, and...)

my $img = gdImageCreateFromPng($fh1);
[...]
gdImageDestroy($img);
$img = gdImageCreateFromPng($fh2);
[...]
gdImageDestroy($img);
$img = gdImageCreateFromPng($fh3);
[...]
gdImageDestroy($img);

Or a simpler solution is to use different variables $img1, $img2, $img3 and so on, and calling gdImageDestroy each time with the LEAVE phaser.

my $img1 = gdImageCreateFromPng($fh1);
LEAVE gdImageDestroy($_) with $img1;
[...]
my $img2 = gdImageCreateFromPng($fh2);
LEAVE gdImageDestroy($_) with $img2;
[...]
my $img3 = gdImageCreateFromPng($fh3);
LEAVE gdImageDestroy($_) with $img3;
[...]

When using a function gdImageXXXPtr to fill a blob with graphic data, the memory management function is gdFree. Usually, the pointer has a very short lifespan. Once the blob has been generated by blob-from-pointer, the pointer is useless and can be fred immediately. A typical chunk of code would be:

use GD::Raw;
use NativeHelpers::Blob;

[...]

my int32 $size;
my $ptr  = gdImagePngPtr($im, $size);
my $blob = blob-from-pointer($ptr, elems => $size, type => Blob[int8]);
gdFree($ptr);

AUTHORS

Dagur Valberg Johannsson
Raku Community

COPYRIGHT AND LICENSE

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.

NAME

SYNOPSIS

DESCRIPTION

FUNCTIONS PORTED TO RAKU

Image Formats

gd.c

Creation and Destruction

Color

Pixels

Primitives

Cloning and Copying

Polygons

Other

gd.h