Pixmap

Data Structures
struct	gp_pixmap
	A pixmap buffer. More...

Macros
#define	GP_PIXEL_IS_CLIPPED(pixmap, x, y)
	Returns true when pixel is clipped out of pixmap.

Functions
gp_pixmap *	gp_pixmap_alloc_ex (gp_size w, gp_size h, gp_pixel_type type, uint32_t stride)
	Allocates a pixmap.
static gp_pixmap *	gp_pixmap_alloc (gp_size w, gp_size h, gp_pixel_type type)
	Allocates a pixmap.
int	gp_pixmap_correction_set (gp_pixmap *self, gp_correction_desc *corr_desc)
	Sets a correction for the pixmap.
static int	gp_pixmap_gamma_set (gp_pixmap *self, float gamma)
	Sets a gamma correction for the pixmap.
static int	gp_pixmap_srgb_set (gp_pixmap *self)
	Sets a sRGB correction for the pixmap.
void	gp_pixmap_free (gp_pixmap *self)
	Frees a pixmap.
static gp_pixmap *	gp_pixmap_from_data (gp_size w, gp_size h, gp_pixel_type type, void *pixels, enum gp_pixmap_init_flags flags)
	Creates a pixmap from a buffer allocated by malloc().

Detailed Description

Macro Definition Documentation

GP_PIXEL_IS_CLIPPED

#define GP_PIXEL_IS_CLIPPED	(		pixmap,
			x,
			y )

Value:

        ((x) < 0 || x >= (typeof(x)) pixmap->w \
        || (y) < 0 || y >= (typeof(y)) pixmap->h) \

Returns true when pixel is clipped out of pixmap.

This macro does not take into account the rotation flags. Pixel has to be rotated with GP_TRANSFORM_POINT() first.

Definition at line 131 of file gp_pixmap.h.

Function Documentation

gp_pixmap_alloc()

static gp_pixmap * gp_pixmap_alloc ( gp_size w, gp_size h, gp_pixel_type type )

inlinestatic

Allocates a pixmap.

This is a shortcut for gp_pixmap_alloc_ex() without the stride parameter (stride set to 0 to be determined by the library).

Parameters

w	A pixmap width.
h	A pixmap height.
type	A pixel type.

Returns

A newly allocated pixmap or NULL in a case of malloc() failure.

Definition at line 185 of file gp_pixmap.h.

References gp_pixmap_alloc_ex().

gp_pixmap_alloc_ex()

gp_pixmap * gp_pixmap_alloc_ex	(	gp_size	w,
		gp_size	h,
		gp_pixel_type	type,
		uint32_t	stride )

Allocates a pixmap.

The pixmap consists of two parts, the gp_pixmap structure and pixels buffer.

Upon creation the pixmap rotation flags are set to (0, 0, 0) and gamma is set to NULL. If gamma correction is needed it has to be initialized by gp_pixmap_gamma_set() or gp_pixmap_srgb_set().

It's possible to allocate a pixmap with zero w and h and in that case the gp_pixmap::pixels pointer will be set to NULL. Such pixmap must be resized with gp_pixmap_resize() to non-zero w and h in order to actually draw any pixels.

The content of gp_pixmap::pixels buffer is undefined.

The pixmap has to be freed with gp_pixmap_free() when no longer needed.

Parameters

w	A pixmap width.
h	A pixmap height.
type	A pixel type.
stride	The length in bytes of an image buffer row. Must be larger or equal than pixel size in bytes multiplied by width. It's determinted automatically when 0 is passed.

Returns

A newly allocated and initialized pixmap.

NULL in a case of failure and errno is set.

Exceptions

EINVAL	Invalid pixel type or stride.
ENOMEM	Memory allocation failure.
EOVERFLOW	One of the multiplications did overflow when pixel buffer size was calculated.

Referenced by gp_pixmap_alloc().

gp_pixmap_correction_set()

int gp_pixmap_correction_set	(	gp_pixmap *	self,
		gp_correction_desc *	corr_desc )

Sets a correction for the pixmap.

If there was a gamma correction allready set for the pixmap the original correction reference counters are decremented and the correction is replaced with a new table.

Parameters

self	A pixmap.
corr_desc	A correction description.

Returns

Zero on success. May fail if underlying malloc() has failed.

Referenced by gp_pixmap_gamma_set(), and gp_pixmap_srgb_set().

gp_pixmap_free()

void gp_pixmap_free

(

gp_pixmap *

self

)

Frees a pixmap.

If pixmap->free_pixels is set also free pixel data, this flag is set automatically by gp_pixmap_alloc() and gp_pixmap_alloc_ex().

Parameters

self	A pixmap to free.

gp_pixmap_from_data()

static gp_pixmap * gp_pixmap_from_data ( gp_size w, gp_size h, gp_pixel_type type, void * pixels, enum gp_pixmap_init_flags flags )

inlinestatic

Creates a pixmap from a buffer allocated by malloc().

This is actually shorthand for allocating the gp_pixmap structure and calling gp_pixmap_init() on the resulting pointer.

Attention

The user has to make sure that the pixels array has correct size and format.

Parameters

w	Pixmap width
h	Pixmap height
type	A pixel type, describes how pixels are organized in the data buffer.
pixels	A pointer to a buffer with the pixel data.
flags	A bitmask or of the enum gp_pixmap_init_flags

Returns

A newly allocated and initialized pixmap or NULL in a case of a failure.

Definition at line 346 of file gp_pixmap.h.

References gp_pixmap_init().

gp_pixmap_gamma_set()

static int gp_pixmap_gamma_set ( gp_pixmap * self, float gamma )

inlinestatic

Sets a gamma correction for the pixmap.

This is a shorthand for:

gp_correction_desc desc = {
        .corr_type = GP_CORRECTION_TYPE_GAMMA,
        .gamma = gamma;
};
 
gp_pixmap_correction_set(self, &desc);

Parameters

self	A pixmap.
gamma	A gamma value.

Returns

Zero on success. May fail if underlying malloc() has failed.

Definition at line 224 of file gp_pixmap.h.

References GP_CORRECTION_TYPE_GAMMA, and gp_pixmap_correction_set().

gp_pixmap_srgb_set()

static int gp_pixmap_srgb_set ( gp_pixmap * self )

inlinestatic

Sets a sRGB correction for the pixmap.

This is a shorthand for:

gp_correction_desc desc = {
        .corr_type = GP_CORRECTION_TYPE_SRGB,
};
 
gp_pixmap_correction_set(self, &desc);

Parameters

self

A pixmap.

Returns

Zero on success. May fail if underlying malloc() has failed.

Definition at line 251 of file gp_pixmap.h.

References GP_CORRECTION_TYPE_SRGB, and gp_pixmap_correction_set().