10a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger#ifndef SkBitmapProcState_utils_DEFINED 20a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger#define SkBitmapProcState_utils_DEFINED 30a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger 40a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger// Helper to ensure that when we shift down, we do it w/o sign-extension 50a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger// so the caller doesn't have to manually mask off the top 16 bits 60a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger// 70a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenbergerstatic unsigned SK_USHIFT16(unsigned x) { 80a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger return x >> 16; 90a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger} 100a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger 110a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger/* 120a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger * The decal_ functions require that 130a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger * 1. dx > 0 140a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger * 2. [fx, fx+dx, fx+2dx, fx+3dx, ... fx+(count-1)dx] are all <= maxX 150a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger * 160a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger * In addition, we use SkFractionalInt to keep more fractional precision than 170a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger * just SkFixed, so we will abort the decal_ call if dx is very small, since 180a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger * the decal_ function just operates on SkFixed. If that were changed, we could 190a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger * skip the very_small test here. 200a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger */ 210a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenbergerstatic inline bool can_truncate_to_fixed_for_decal(SkFractionalInt frX, 220a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger SkFractionalInt frDx, 230a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger int count, unsigned max) { 240a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger SkFixed dx = SkFractionalIntToFixed(frDx); 250a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger 260a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger // if decal_ kept SkFractionalInt precision, this would just be dx <= 0 270a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger // I just made up the 1/256. Just don't want to perceive accumulated error 280a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger // if we truncate frDx and lose its low bits. 290a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger if (dx <= SK_Fixed1 / 256) { 300a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger return false; 310a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger } 320a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger 330a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger // We cast to unsigned so we don't have to check for negative values, which 340a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger // will now appear as very large positive values, and thus fail our test! 350a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger SkFixed fx = SkFractionalIntToFixed(frX); 360a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger return (unsigned)SkFixedFloorToInt(fx) <= max && 370a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger (unsigned)SkFixedFloorToInt(fx + dx * (count - 1)) < max; 380a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger} 390a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger 400a657bbc2c6fc9daf699942e023050536d5ec95fDerek Sollenberger#endif /* #ifndef SkBitmapProcState_utils_DEFINED */ 41