fitz/bitmap.h

Index

typedef

• fz_halftone

struct

• fz_bitmap

function

• fz_bitmap_details
• fz_clear_bitmap
• fz_default_halftone
• fz_drop_bitmap
• fz_drop_halftone
• fz_invert_bitmap
• fz_keep_bitmap
• fz_keep_halftone
• fz_new_bitmap
• fz_new_bitmap_from_image
• fz_new_bitmap_from_pixmap
• fz_new_bitmap_from_pixmap_band

Bitmap

struct fz_bitmap

struct fz_bitmap
{
        int refs;
        int w, h, stride, n;
        int xres, yres;
        unsigned char *samples;
}

Bitmaps have 1 bit per component. Only used for creating halftoned versions of contone buffers, and saving out. Samples are stored msb first, akin to pbms.

The internals of this struct are considered implementation details and subject to change. Where possible, accessor functions should be used in preference.

function fz_keep_bitmap

fz_bitmap *
fz_keep_bitmap (
        fz_context *ctx,
        fz_bitmap *bit
)

Take an additional reference to the bitmap. The same pointer is returned.

Never throws exceptions.

function fz_drop_bitmap

void
fz_drop_bitmap (
        fz_context *ctx,
        fz_bitmap *bit
)

Drop a reference to the bitmap. When the reference count reaches zero, the bitmap will be destroyed.

Never throws exceptions.

function fz_invert_bitmap

void
fz_invert_bitmap (
        fz_context *ctx,
        fz_bitmap *bmp
)

Invert bitmap.

Never throws exceptions.

typedef fz_halftone

typedef struct fz_halftone fz_halftone

A halftone is a set of threshold tiles, one per component. Each threshold tile is a pixmap, possibly of varying sizes and phases. Currently, we only provide one ‘default’ halftone tile for operating on 1 component plus alpha pixmaps (where the alpha is ignored). This is signified by a fz_halftone pointer to NULL.

function fz_new_bitmap_from_pixmap

fz_bitmap *
fz_new_bitmap_from_pixmap (
        fz_context *ctx,
        fz_pixmap *pix,
        fz_halftone *ht
)

Make a bitmap from a pixmap and a halftone.

pix:

The pixmap to generate from. Currently must be a single color component with no alpha.

ht:

The halftone to use. NULL implies the default halftone.

Returns the resultant bitmap. Throws exceptions in the case of failure to allocate.

function fz_new_bitmap_from_image

fz_bitmap *
fz_new_bitmap_from_image (
        fz_context *ctx,
        fz_image *img,
        fz_halftone *ht
)

Make a bitmap from a pixmap and a halftone.

img:

The image to generate from. Currently must be a single color component with no alpha.

ht:

The halftone to use. NULL implies the default halftone.

Returns the resultant bitmap. Throws exceptions in the case of failure to allocate.

function fz_new_bitmap_from_pixmap_band

fz_bitmap *
fz_new_bitmap_from_pixmap_band (
        fz_context *ctx,
        fz_pixmap *pix,
        fz_halftone *ht,
        int band_start
)

Make a bitmap from a pixmap and a halftone, allowing for the position of the pixmap within an overall banded rendering.

pix:

The pixmap to generate from. Currently must be a single color component with no alpha.

ht:

The halftone to use. NULL implies the default halftone.

band_start:

Vertical offset within the overall banded rendering (in pixels)

Returns the resultant bitmap. Throws exceptions in the case of failure to allocate.

function fz_new_bitmap

fz_bitmap *
fz_new_bitmap (
        fz_context *ctx,
        int w,
        int h,
        int n,
        int xres,
        int yres
)

Create a new bitmap.

w, h:

Width and Height for the bitmap

n:

Number of color components (assumed to be a divisor of 8)

xres, yres:

X and Y resolutions (in pixels per inch).

Returns pointer to created bitmap structure. The bitmap data is uninitialised.

function fz_bitmap_details

void
fz_bitmap_details (
        fz_bitmap *bitmap,
        int *w,
        int *h,
        int *n,
        int *stride
)

Retrieve details of a given bitmap.

bitmap:

The bitmap to query.

w:

Pointer to storage to retrieve width (or NULL).

h:

Pointer to storage to retrieve height (or NULL).

n:

Pointer to storage to retrieve number of color components (or NULL).

stride:

Pointer to storage to retrieve bitmap stride (or NULL).

function fz_clear_bitmap

void
fz_clear_bitmap (
        fz_context *ctx,
        fz_bitmap *bit
)

Set the entire bitmap to 0.

Never throws exceptions.

function fz_default_halftone

fz_halftone *
fz_default_halftone (
        fz_context *ctx,
        int num_comps
)

Create a ‘default’ halftone structure for the given number of components.

num_comps:

The number of components to use.

Returns a simple default halftone. The default halftone uses the same halftone tile for each plane, which may not be ideal for all purposes.

function fz_keep_halftone

fz_halftone *
fz_keep_halftone (
        fz_context *ctx,
        fz_halftone *half
)

Take an additional reference to the halftone. The same pointer is returned.

Never throws exceptions.

function fz_drop_halftone

void
fz_drop_halftone (
        fz_context *ctx,
        fz_halftone *ht
)

Drop a reference to the halftone. When the reference count reaches zero, the halftone is destroyed.

Never throws exceptions.