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|
=encoding UTF-8
=head1 NAME
BH_Bitmap - bitmap/image access
=head1 SYNTAX
#include <BH/Bitmap.h>
cc prog.c -o prog -lbh
=head1 DESCRIPTION
The BH_Bitmap module provides methods for accessing the pixel data of a bitmap
(image) and for converting between different pixel formats.
=head1 FORMATS
Currently, the following pixel formats are supported:
=over
=item B<BH_BITMAP_INDEX1>
1-bit indexed/paletted
=item B<BH_BITMAP_INDEX2>
2-bit indexed/paletted
=item B<BH_BITMAP_INDEX4>
4-bit indexed/paletted
=item B<BH_BITMAP_INDEX8>
8-bit indexed/paletted
=item B<BH_BITMAP_GRAY8>
8-bit grayscale
=item B<BH_BITMAP_GRAY16>
16-bit grayscale
=item B<BH_BITMAP_RGBA32>
32-bit RGB with alpha represented in uint32_t value. The layout is: 0xAARRGGBB
=item B<BH_BITMAP_RGBA64>
64-bit RGB with alpha represented in uint64_t value. The layout is:
0xAAAARRRRGGGGBBBB
=item B<BH_BITMAP_RGB565>
16-bit RGB
=item B<BH_BITMAP_RGB888>
24-bit RGB
=item B<BH_BITMAP_RGBA8888>
32-bit RGB with alpha
=item B<BH_BITMAP_RGB161616>
48-bit RGB
=item B<BH_BITMAP_RGBA16161616>
64-bit RGB with alpha
=item B<BH_BITMAP_RGBA1010102>
32-bit RGB with alpha
=back
All pixel formats use the current machine endianness.
The flag I<BH_BITMAP_BGR> can be used to change the order of the color channels
(RGB -> BGR). The flag has no effect on the following pixel formats:
I<BH_BITMAP_INDEX1>, I<BH_BITMAP_INDEX2>, I<BH_BITMAP_INDEX4>,
I<BH_BITMAP_INDEX8>, I<BH_BITMAP_GRAY8>, I<BH_BITMAP_GRAY16>,
I<BH_BITMAP_RGBA32> and I<BH_BITMAP_RGBA64>.
The flag I<BH_BITMAP_LSB> can be used to change the start of the bit order for
indexed images. This flag only affects the following pixel formats:
I<BH_BITMAP_INDEX1>, I<BH_BITMAP_INDEX2>, I<BH_BITMAP_INDEX4> and
I<BH_BITMAP_INDEX8>.
The flag I<BH_BITMAP_NOALPHA> can be used to indicate that the alpha channel is
not used and should always be set to the maximum value (255 for 8-bit and 65535
for 16-bit).
The flag I<BH_BITMAP_PREMULT> can be used to indicate that color values are in
premultiplied form.
The color palette is assumed to contain exactly 256 colors and is stored in the
I<BH_BITMAP_RGBA32> pixel format.
=head1 API CALLS
=head2 BH_BitmapNew
BH_Bitmap *BH_BitmapNew(uint32_t width,
uint32_t height,
int format,
int flags,
void *data,
void *palette);
Creates the bitmap with the specified I<width>, I<height> and pixel I<format>.
The I<flags> parameter can take a combination of the following values:
=over
=item B<BH_BITMAP_FLAG_ALIGN32>
Rows are aligned to 32-bit boundary
=back
The optional I<data> parameter specifies pointer to the existing data.
The optional I<palette> parameter specifies pointer to the existing palette.
This function returns a pointer to a new BH_Bitmap object or NULL.
=head2 BH_BitmapFree
void BH_BitmapFree(BH_Bitmap *bitmap);
Destroys the bitmap object.
=head2 BH_BitmapColor
void BH_BitmapColor(const BH_Bitmap *bitmap,
uint32_t x,
uint32_t y,
BH_Color *value);
Reads color value of the pixel at specified position.
The I<x> and I<y> parameters specify a position on the bitmap.
=head2 BH_BitmapSetColor
void BH_BitmapSetColor(BH_Bitmap *bitmap,
uint32_t x,
uint32_t y,
const BH_Color *value);
Writes color value of the pixel at specified position.
The I<x> and I<y> parameters specify a position on the bitmap.
=head2 BH_BitmapIndex
uint8_t BH_BitmapIndex(const BH_Bitmap *bitmap,
uint32_t x,
uint32_t y);
Returns the index value at the specified position.
The I<x> and I<y> parameters specify a position on the bitmap.
=head2 BH_BitmapSetIndex
void BH_BitmapSetIndex(BH_Bitmap *bitmap,
uint32_t x,
uint32_t y,
uint8_t index);
Sets the index value at the specified position.
The I<x> and I<y> parameters specify a position on the bitmap.
=head2 BH_BitmapCopy
BH_Bitmap *BH_BitmapCopy(BH_Bitmap *bitmap,
uint32_t x,
uint32_t y,
uint32_t width,
uint32_t height,
int shallow);
Creates a copy of the bitmap region by the given position and size.
The I<x> and I<y> parameters specify a position on the bitmap.
The I<width> and I<height> parameters specify size of the new bitmap.
The I<shallow> parameter specifies whether the new bitmap is a shallow copy (or
a view) of the existing bitmap or a deep copy. For the shallow copy to work, the
region should be within the existing bitmap.
This function returns a pointer to a new BH_Bitmap object or NULL.
=head2 BH_BitmapScanline
void *BH_BitmapScanline(const BH_Bitmap *bitmap,
uint32_t y);
Returns address of the scanline in the bitmap.
=head2 BH_BitmapAt
void *BH_BitmapAt(const BH_Bitmap *bitmap,
uint32_t x,
uint32_t y);
Returns address of the pixel in the bitmap.
=head2 BH_BitmapWidth
uint32_t BH_BitmapWidth(BH_Bitmap *bitmap);
Returns width of the bitmap.
=head2 BH_BitmapHeight
uint32_t BH_BitmapHeight(BH_Bitmap *bitmap);
Returns height of the bitmap.
=head2 BH_BitmapFormat
int BH_BitmapFormat(BH_Bitmap *bitmap);
Returns pixel format of the bitmap.
=head2 BH_BitmapStride
size_t BH_BitmapStride(BH_Bitmap *bitmap);
Returns row stride of the bitmap.
=head2 BH_BitmapData
void *BH_BitmapData(BH_Bitmap *bitmap);
Returns pointer to the pixel data of the bitmap.
=head2 BH_BitmapPalette
void *BH_BitmapPalette(BH_Bitmap *bitmap);
Returns pointer to the bitmap's palette.
=head2 BH_BitmapFlags
int BH_BitmapFlags(BH_Bitmap *bitmap);
Returns bitmap's flags.
The result can be a combination of the following values:
=over
=item B<BH_BITMAP_FLAG_ALIGN32>
Rows are aligned to 32-bit boundary
=item B<BH_BITMAP_FLAG_EXT_DATA>
Bitmap doesn't own the pixel data
=item B<BH_BITMAP_FLAG_EXT_PALETTE>
Bitmap doesn't own palette data
=back
=head2 BH_BitmapConvertRow
void BH_BitmapConvertRow(void *src,
int srcFormat,
void *srcPalette,
void *dest,
int destFormat,
void *destPalette,
size_t count);
Converts a row of source data from one pixel format to another pixel format.
The parameter I<src> and I<srcFormat> specify the source of the data and its
pixel format.
The parameter I<srcPalette> specify the source palette (if required by the pixel
format).
The parameter I<dest> and I<destFormat> specify the destination of the data and
its pixel format.
The parameter I<destPalette> specify the destination palette (if required by the
pixel format).
The parameter I<count> specifies the number of pixel for conversion.
=head1 SEE ALSO
L<BH>
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