1 #ifndef SkBitmapProcState_utils_DEFINED 2 #define SkBitmapProcState_utils_DEFINED 3 4 // Helper to ensure that when we shift down, we do it w/o sign-extension 5 // so the caller doesn't have to manually mask off the top 16 bits 6 // 7 static unsigned SK_USHIFT16(unsigned x) { 8 return x >> 16; 9 } 10 11 /* 12 * The decal_ functions require that 13 * 1. dx > 0 14 * 2. [fx, fx+dx, fx+2dx, fx+3dx, ... fx+(count-1)dx] are all <= maxX 15 * 16 * In addition, we use SkFractionalInt to keep more fractional precision than 17 * just SkFixed, so we will abort the decal_ call if dx is very small, since 18 * the decal_ function just operates on SkFixed. If that were changed, we could 19 * skip the very_small test here. 20 */ 21 static inline bool can_truncate_to_fixed_for_decal(SkFractionalInt frX, 22 SkFractionalInt frDx, 23 int count, unsigned max) { 24 SkFixed dx = SkFractionalIntToFixed(frDx); 25 26 // if decal_ kept SkFractionalInt precision, this would just be dx <= 0 27 // I just made up the 1/256. Just don't want to perceive accumulated error 28 // if we truncate frDx and lose its low bits. 29 if (dx <= SK_Fixed1 / 256) { 30 return false; 31 } 32 33 // We cast to unsigned so we don't have to check for negative values, which 34 // will now appear as very large positive values, and thus fail our test! 35 SkFixed fx = SkFractionalIntToFixed(frX); 36 return (unsigned)SkFixedFloorToInt(fx) <= max && 37 (unsigned)SkFixedFloorToInt(fx + dx * (count - 1)) < max; 38 } 39 40 #endif /* #ifndef SkBitmapProcState_utils_DEFINED */ 41
