DefaultPaletteManager Class Reference

#include <default-palette.h>

Inheritance diagram for DefaultPaletteManager:

Public Member Functions
void	setPalette (const byte *colors, uint start, uint num)
void	grabPalette (byte *colors, uint start, uint num) const

Protected Member Functions
virtual void	setPaletteIntern (const byte *colors, uint start, uint num)=0

Protected Attributes
byte	_palette [3 *256]

Detailed Description

This is a default implementation of the PaletteManager interface which ensures that grabPalette works as specified. Of course it is still necessary to provide code that actually updates the (possibly emulated) "hardware" palette of the backend. For this purpose, implement the abstract setPaletteIntern method.

Member Function Documentation

setPaletteIntern()

virtual void DefaultPaletteManager::setPaletteIntern ( const byte *  colors, uint  start, uint  num  )

protectedpure virtual

Subclasses should only implement this method and none of the others. Its semantics are like that of setPalette, only that it does not need to worry about making it possible to query the palette values once they have been set.

setPalette()

void DefaultPaletteManager::setPalette ( const byte *  colors, uint  start, uint  num  )

inlinevirtual

Replace the specified range of the palette with new colors. The palette entries from 'start' till (start+num-1) will be replaced - so a full palette update is accomplished via start=0, num=256.

The palette data is specified in interleaved RGB format. That is, the first byte of the memory block 'colors' points at is the red component of the first new color; the second byte the green component of the first new color; the third byte the blue component, the last byte to the alpha (transparency) value. Then the second color starts, and so on. So memory looks like this: R1-G1-B1-R2-G2-B2-R3-...

Parameters

colors	the new palette data, in interleaved RGB format
start	the first palette entry to be updated
num	the number of palette entries to be updated

Note

It is an error if start+num exceeds 256, behavior is undefined in that case (the backend may ignore it silently or assert).

It is an error if this function gets called when the pixel format in use (the return value of getScreenFormat) has more than one byte per pixel.

See also

getScreenFormat

Implements PaletteManager.

grabPalette()

void DefaultPaletteManager::grabPalette ( byte *  colors, uint  start, uint  num  ) const

inlinevirtual

Grabs a specified part of the currently active palette. The format is the same as for setPalette.

This should return exactly the same RGB data as was setup via previous setPalette calls.

For example, for every valid value of start and num of the following code:

byte origPal[num*3]; // Setup origPal's data however you like g_system->setPalette(origPal, start, num); byte obtainedPal[num*3]; g_system->grabPalette(obtainedPal, start, num);

the following should be true:

memcmp(origPal, obtainedPal, num*3) == 0

See also

setPalette

Parameters

colors	the palette data, in interleaved RGB format
start	the first platte entry to be read
num	the number of palette entries to be read

Note

It is an error if this function gets called when the pixel format in use (the return value of getScreenFormat) has more than one byte per pixel.

See also

getScreenFormat

Implements PaletteManager.

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The documentation for this class was generated from the following file:

• backends/graphics/default-palette.h