Systems and methods are presented for processing and rendering image data during a single pass through the image data. A method includes loading scanlines of image data into a rolling band buffer, performing a windowing technique on the image data, and determining if a class change was experienced by any window having a portion in an output scanline of the buffer. The method further includes processing image data in the output scanline for a window portion that experienced a class change, using a blended rendering algorithm. If no class change is detected, the method includes processing image data in the output scanline for the window portion using a class-based rendering algorithm. The method optionally includes rendering processed image data for the output scanline to a rendering device. According to other features, an apparatus includes a rolling band buffer, a windowing processor, class-based rendering algorithms, and a blended rendering algorithm.