| |
| /* |
| * Copyright 2010 The Android Open Source Project |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| |
| #include "SkScalar.h" |
| |
| SkScalar SkScalarInterpFunc(SkScalar searchKey, const SkScalar keys[], |
| const SkScalar values[], int length) { |
| SkASSERT(length > 0); |
| SkASSERT(keys != NULL); |
| SkASSERT(values != NULL); |
| #ifdef SK_DEBUG |
| for (int i = 1; i < length; i++) |
| SkASSERT(keys[i] >= keys[i-1]); |
| #endif |
| int right = 0; |
| while (right < length && searchKey > keys[right]) |
| right++; |
| // Could use sentinel values to eliminate conditionals, but since the |
| // tables are taken as input, a simpler format is better. |
| if (length == right) |
| return values[length-1]; |
| if (0 == right) |
| return values[0]; |
| // Otherwise, interpolate between right - 1 and right. |
| SkScalar rightKey = keys[right]; |
| SkScalar leftKey = keys[right-1]; |
| SkScalar fract = SkScalarDiv(searchKey-leftKey,rightKey-leftKey); |
| return SkScalarInterp(values[right-1], values[right], fract); |
| } |