The IlvIndexedBitmapData Class

Foundation > Graphic Formats > IlvBitmapData: The Portable Bitmap Data Management Class > The IlvIndexedBitmapData Class

The IlvIndexedBitmapData class is dedicated to indexed color images, where raster data is described as indexes to a color map (8-bit values, meaning that you can have only 256 colors in an indexed bitmap data).

Creating an Indexed Bitmap Data of Dimensions 256 * 256 Pixels

The first step is to create a colormap. We create a colormap with 256 entries. We then fill this colormap with grayscale values. Each component is described using 8 bits for each component.

IlvColorMap* cmap = new IlvColorMap(256);

for (IlUInt idx = 0; idx < 256; ++idx) {

// sets the red, green and blue components for a entry

cmap->setEntry(idx, idx, idx, idx);

}

We then create an indexed bitmap data of desired size:

IlvIndexedBitmapData* idata = new IlvIndexedBitmapData(256, 256, cmap);

We then fill the bitmap data with a gradient of indexes:

for (IlUInt h = 0; h < 256; ++h)

for (IlUInt w = 0; w < 256; ++w)

idata->setPixel(w, h, h);

To be able to display this bitmap data on the screen, you have to create an IlvBitmap from it.

IlvBitmap* bitmap = new IlvBitmap(display, idata);

You can then use the IlvIcon class to create a graphic object from this.

Version 6.0