The target polygon may be larger or smaller than the texture, and the number of vertexes of the polygon may not agree with that of the texture. In that case, the texture map has to undergo filtering, including perhaps magnification or minification. In the nearest method of filtering, the texel with coordinates nearest the center of the pixel is used for both magnification and minification. In the linear method of filtering, a weighted linear average of the four texels nearest to the center of the pixel is used for both magnification and minification. The following sample images illustrate the nearest and linear filters.
Performance is better with the nearest filtering but the result can be jaggy.