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The CairoFormat class

(PECL cairo >= 0.1.0)


CairoFormat enums are used to identify the memory format of the image data.

Class synopsis

CairoFormat {
/* Constants */
const integer ARGB32 = 0 ;
const integer RGB24 = 1 ;
const integer A8 = 2 ;
const integer A1 = 3 ;
/* Methods */
public static int strideForWidth ( int $format , int $width )

Predefined Constants


Each pixel is a 32-bit quantity, with alpha in the upper 8 bits, then red, then green, then blue. The 32-bit quantities are stored native-endian. Pre-multiplied alpha is used. (That is, 50% transparent red is 0x80800000, not 0x80ff0000.)


Each pixel is a 32-bit quantity, with the upper 8 bits unused. Red, Green, and Blue are stored in the remaining 24 bits in that order.


Each pixel is a 8-bit quantity holding an alpha value.


Each pixel is a 1-bit quantity holding an alpha value. Pixels are packed together into 32-bit quantities. The ordering of the bits matches the endianess of the platform. On a big-endian machine, the first pixel is in the uppermost bit, on a little-endian machine the first pixel is in the least-significant bit.

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