Palette for 4 and 8-bit images.
◆ oslCreatePaletteEx()
| OSL_PALETTE * oslCreatePaletteEx |
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int | size, |
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int | location, |
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short | pixelFormat ) |
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extern |
Creates a new (empty) palette with the specified pixel format.
This function creates a new palette that can be used with 4-bit or 8-bit images. The palette is allocated in the specified location and uses the provided pixel format. For most cases, the pixel format should be `OSL_PF_8888` as palettes are generally small in size.
@param size
The number of colors in the palette. For example, a 4-bit image palette will have 16 colors (2^4), and an 8-bit image palette will have 256 colors (2^8).
@param location
The memory location where the palette will be stored. Use `OSL_IN_RAM` to allocate the palette in RAM.
@param pixelFormat
The pixel format of each palette entry. Typically, this should be `OSL_PF_8888` to match the common palette size.
\b Note:
- After creating and filling the palette, it is essential to uncache it to ensure that changes are applied correctly.
- If you need to uncache both the image and its palette, you can use `oslUncacheImage(img)` which will also uncache the palette.
\b Example:
\code
OSL_IMAGE *img = oslCreateImage(32, 32, OSL_IN_RAM, OSL_PF_4BIT);
// Determine the palette size based on the image's pixel format.
int palSize = 1 << osl_paletteSizes[img->pixelFormat];
// Create the palette with the required size.
img->palette = oslCreatePaletteEx(palSize, OSL_IN_RAM, OSL_PF_8888);
// Get a pointer to the palette data.
u32 *paletteData = (u32*)img->palette->data;
// Set all entries to bright opaque red.
for (int i = 0; i < img->palette->nElements; i++)
paletteData[i] = RGBA(255, 0, 0, 255);
// Uncache the palette after finishing.
oslUncachePalette(img->palette);
// Alternatively, uncache the image which also uncaches the palette.
// oslUncacheImage(img);
\endcode
◆ oslCreatePaletteFrom()
| OSL_PALETTE * oslCreatePaletteFrom |
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void * | data, |
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int | size, |
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short | pixelFormat ) |
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extern |
Creates a palette from existing data.
This function creates a palette using data that already exists. The data is not copied; it is used directly. You need to specify the size of the palette and the pixel format of the data.
@param data
Pointer to the existing palette data.
@param size
The number of colors in the palette.
@param pixelFormat
The pixel format of each palette entry.
@return
A pointer to the newly created palette.
\b Note:
- The data is not copied; it is used as is. Ensure that the data remains valid for the lifetime of the palette.
- Only the `OSL_PALETTE` structure is freed when the palette is deleted; the data is not affected.
\b Example:
\code
void *existingData = existing palette data;
OSL_PALETTE *palette = oslCreatePaletteFrom(existingData, 256, OSL_PF_8888);
\endcode
◆ oslDeletePalette()
Deletes an existing palette.
This function frees the memory used by an `OSL_PALETTE` structure. If the palette was created using `oslCreatePaletteFrom`, the data used to create the palette is not freed.
@param p
Pointer to the palette to be deleted.
\b Example:
\code
oslDeletePalette(palette);
\endcode
◆ oslGetPaletteColor()
Returns a color entry from a palette.
This function retrieves a color from the palette at a specified index. The color value is in the same pixel format as the palette.
@param p
Pointer to the palette.
@param index
The index of the color entry to retrieve.
@return
The color value at the specified index.
\b Example:
\code
int color = oslGetPaletteColor(palette, 0);
\endcode
◆ oslUncachePalette()
Uncaches a palette.
After accessing palette data in a cached way (e.g., through `pal->data`), you must uncache the palette to ensure changes are applied correctly.
@param pal
Pointer to the palette to uncache.
\b Example:
\code
oslUncachePalette(palette);
\endcode
1.12.0