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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /media/libyuv/source/scale_common.cc
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
Diffstat (limited to 'media/libyuv/source/scale_common.cc')
-rw-r--r--media/libyuv/source/scale_common.cc1159
1 files changed, 1159 insertions, 0 deletions
diff --git a/media/libyuv/source/scale_common.cc b/media/libyuv/source/scale_common.cc
new file mode 100644
index 000000000..3507aa4d9
--- /dev/null
+++ b/media/libyuv/source/scale_common.cc
@@ -0,0 +1,1159 @@
+/*
+ * Copyright 2013 The LibYuv Project Authors. All rights reserved.
+ *
+ * Use of this source code is governed by a BSD-style license
+ * that can be found in the LICENSE file in the root of the source
+ * tree. An additional intellectual property rights grant can be found
+ * in the file PATENTS. All contributing project authors may
+ * be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "libyuv/scale.h"
+
+#include <assert.h>
+#include <string.h>
+
+#include "libyuv/cpu_id.h"
+#include "libyuv/planar_functions.h" // For CopyARGB
+#include "libyuv/row.h"
+#include "libyuv/scale_row.h"
+
+#ifdef __cplusplus
+namespace libyuv {
+extern "C" {
+#endif
+
+static __inline int Abs(int v) {
+ return v >= 0 ? v : -v;
+}
+
+// CPU agnostic row functions
+void ScaleRowDown2_C(const uint8* src_ptr, ptrdiff_t src_stride,
+ uint8* dst, int dst_width) {
+ int x;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = src_ptr[1];
+ dst[1] = src_ptr[3];
+ dst += 2;
+ src_ptr += 4;
+ }
+ if (dst_width & 1) {
+ dst[0] = src_ptr[1];
+ }
+}
+
+void ScaleRowDown2_16_C(const uint16* src_ptr, ptrdiff_t src_stride,
+ uint16* dst, int dst_width) {
+ int x;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = src_ptr[1];
+ dst[1] = src_ptr[3];
+ dst += 2;
+ src_ptr += 4;
+ }
+ if (dst_width & 1) {
+ dst[0] = src_ptr[1];
+ }
+}
+
+void ScaleRowDown2Linear_C(const uint8* src_ptr, ptrdiff_t src_stride,
+ uint8* dst, int dst_width) {
+ const uint8* s = src_ptr;
+ int x;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = (s[0] + s[1] + 1) >> 1;
+ dst[1] = (s[2] + s[3] + 1) >> 1;
+ dst += 2;
+ s += 4;
+ }
+ if (dst_width & 1) {
+ dst[0] = (s[0] + s[1] + 1) >> 1;
+ }
+}
+
+void ScaleRowDown2Linear_16_C(const uint16* src_ptr, ptrdiff_t src_stride,
+ uint16* dst, int dst_width) {
+ const uint16* s = src_ptr;
+ int x;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = (s[0] + s[1] + 1) >> 1;
+ dst[1] = (s[2] + s[3] + 1) >> 1;
+ dst += 2;
+ s += 4;
+ }
+ if (dst_width & 1) {
+ dst[0] = (s[0] + s[1] + 1) >> 1;
+ }
+}
+
+void ScaleRowDown2Box_C(const uint8* src_ptr, ptrdiff_t src_stride,
+ uint8* dst, int dst_width) {
+ const uint8* s = src_ptr;
+ const uint8* t = src_ptr + src_stride;
+ int x;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = (s[0] + s[1] + t[0] + t[1] + 2) >> 2;
+ dst[1] = (s[2] + s[3] + t[2] + t[3] + 2) >> 2;
+ dst += 2;
+ s += 4;
+ t += 4;
+ }
+ if (dst_width & 1) {
+ dst[0] = (s[0] + s[1] + t[0] + t[1] + 2) >> 2;
+ }
+}
+
+void ScaleRowDown2Box_Odd_C(const uint8* src_ptr, ptrdiff_t src_stride,
+ uint8* dst, int dst_width) {
+ const uint8* s = src_ptr;
+ const uint8* t = src_ptr + src_stride;
+ int x;
+ dst_width -= 1;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = (s[0] + s[1] + t[0] + t[1] + 2) >> 2;
+ dst[1] = (s[2] + s[3] + t[2] + t[3] + 2) >> 2;
+ dst += 2;
+ s += 4;
+ t += 4;
+ }
+ if (dst_width & 1) {
+ dst[0] = (s[0] + s[1] + t[0] + t[1] + 2) >> 2;
+ dst += 1;
+ s += 2;
+ t += 2;
+ }
+ dst[0] = (s[0] + t[0] + 1) >> 1;
+}
+
+void ScaleRowDown2Box_16_C(const uint16* src_ptr, ptrdiff_t src_stride,
+ uint16* dst, int dst_width) {
+ const uint16* s = src_ptr;
+ const uint16* t = src_ptr + src_stride;
+ int x;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = (s[0] + s[1] + t[0] + t[1] + 2) >> 2;
+ dst[1] = (s[2] + s[3] + t[2] + t[3] + 2) >> 2;
+ dst += 2;
+ s += 4;
+ t += 4;
+ }
+ if (dst_width & 1) {
+ dst[0] = (s[0] + s[1] + t[0] + t[1] + 2) >> 2;
+ }
+}
+
+void ScaleRowDown4_C(const uint8* src_ptr, ptrdiff_t src_stride,
+ uint8* dst, int dst_width) {
+ int x;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = src_ptr[2];
+ dst[1] = src_ptr[6];
+ dst += 2;
+ src_ptr += 8;
+ }
+ if (dst_width & 1) {
+ dst[0] = src_ptr[2];
+ }
+}
+
+void ScaleRowDown4_16_C(const uint16* src_ptr, ptrdiff_t src_stride,
+ uint16* dst, int dst_width) {
+ int x;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = src_ptr[2];
+ dst[1] = src_ptr[6];
+ dst += 2;
+ src_ptr += 8;
+ }
+ if (dst_width & 1) {
+ dst[0] = src_ptr[2];
+ }
+}
+
+void ScaleRowDown4Box_C(const uint8* src_ptr, ptrdiff_t src_stride,
+ uint8* dst, int dst_width) {
+ intptr_t stride = src_stride;
+ int x;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = (src_ptr[0] + src_ptr[1] + src_ptr[2] + src_ptr[3] +
+ src_ptr[stride + 0] + src_ptr[stride + 1] +
+ src_ptr[stride + 2] + src_ptr[stride + 3] +
+ src_ptr[stride * 2 + 0] + src_ptr[stride * 2 + 1] +
+ src_ptr[stride * 2 + 2] + src_ptr[stride * 2 + 3] +
+ src_ptr[stride * 3 + 0] + src_ptr[stride * 3 + 1] +
+ src_ptr[stride * 3 + 2] + src_ptr[stride * 3 + 3] +
+ 8) >> 4;
+ dst[1] = (src_ptr[4] + src_ptr[5] + src_ptr[6] + src_ptr[7] +
+ src_ptr[stride + 4] + src_ptr[stride + 5] +
+ src_ptr[stride + 6] + src_ptr[stride + 7] +
+ src_ptr[stride * 2 + 4] + src_ptr[stride * 2 + 5] +
+ src_ptr[stride * 2 + 6] + src_ptr[stride * 2 + 7] +
+ src_ptr[stride * 3 + 4] + src_ptr[stride * 3 + 5] +
+ src_ptr[stride * 3 + 6] + src_ptr[stride * 3 + 7] +
+ 8) >> 4;
+ dst += 2;
+ src_ptr += 8;
+ }
+ if (dst_width & 1) {
+ dst[0] = (src_ptr[0] + src_ptr[1] + src_ptr[2] + src_ptr[3] +
+ src_ptr[stride + 0] + src_ptr[stride + 1] +
+ src_ptr[stride + 2] + src_ptr[stride + 3] +
+ src_ptr[stride * 2 + 0] + src_ptr[stride * 2 + 1] +
+ src_ptr[stride * 2 + 2] + src_ptr[stride * 2 + 3] +
+ src_ptr[stride * 3 + 0] + src_ptr[stride * 3 + 1] +
+ src_ptr[stride * 3 + 2] + src_ptr[stride * 3 + 3] +
+ 8) >> 4;
+ }
+}
+
+void ScaleRowDown4Box_16_C(const uint16* src_ptr, ptrdiff_t src_stride,
+ uint16* dst, int dst_width) {
+ intptr_t stride = src_stride;
+ int x;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = (src_ptr[0] + src_ptr[1] + src_ptr[2] + src_ptr[3] +
+ src_ptr[stride + 0] + src_ptr[stride + 1] +
+ src_ptr[stride + 2] + src_ptr[stride + 3] +
+ src_ptr[stride * 2 + 0] + src_ptr[stride * 2 + 1] +
+ src_ptr[stride * 2 + 2] + src_ptr[stride * 2 + 3] +
+ src_ptr[stride * 3 + 0] + src_ptr[stride * 3 + 1] +
+ src_ptr[stride * 3 + 2] + src_ptr[stride * 3 + 3] +
+ 8) >> 4;
+ dst[1] = (src_ptr[4] + src_ptr[5] + src_ptr[6] + src_ptr[7] +
+ src_ptr[stride + 4] + src_ptr[stride + 5] +
+ src_ptr[stride + 6] + src_ptr[stride + 7] +
+ src_ptr[stride * 2 + 4] + src_ptr[stride * 2 + 5] +
+ src_ptr[stride * 2 + 6] + src_ptr[stride * 2 + 7] +
+ src_ptr[stride * 3 + 4] + src_ptr[stride * 3 + 5] +
+ src_ptr[stride * 3 + 6] + src_ptr[stride * 3 + 7] +
+ 8) >> 4;
+ dst += 2;
+ src_ptr += 8;
+ }
+ if (dst_width & 1) {
+ dst[0] = (src_ptr[0] + src_ptr[1] + src_ptr[2] + src_ptr[3] +
+ src_ptr[stride + 0] + src_ptr[stride + 1] +
+ src_ptr[stride + 2] + src_ptr[stride + 3] +
+ src_ptr[stride * 2 + 0] + src_ptr[stride * 2 + 1] +
+ src_ptr[stride * 2 + 2] + src_ptr[stride * 2 + 3] +
+ src_ptr[stride * 3 + 0] + src_ptr[stride * 3 + 1] +
+ src_ptr[stride * 3 + 2] + src_ptr[stride * 3 + 3] +
+ 8) >> 4;
+ }
+}
+
+void ScaleRowDown34_C(const uint8* src_ptr, ptrdiff_t src_stride,
+ uint8* dst, int dst_width) {
+ int x;
+ assert((dst_width % 3 == 0) && (dst_width > 0));
+ for (x = 0; x < dst_width; x += 3) {
+ dst[0] = src_ptr[0];
+ dst[1] = src_ptr[1];
+ dst[2] = src_ptr[3];
+ dst += 3;
+ src_ptr += 4;
+ }
+}
+
+void ScaleRowDown34_16_C(const uint16* src_ptr, ptrdiff_t src_stride,
+ uint16* dst, int dst_width) {
+ int x;
+ assert((dst_width % 3 == 0) && (dst_width > 0));
+ for (x = 0; x < dst_width; x += 3) {
+ dst[0] = src_ptr[0];
+ dst[1] = src_ptr[1];
+ dst[2] = src_ptr[3];
+ dst += 3;
+ src_ptr += 4;
+ }
+}
+
+// Filter rows 0 and 1 together, 3 : 1
+void ScaleRowDown34_0_Box_C(const uint8* src_ptr, ptrdiff_t src_stride,
+ uint8* d, int dst_width) {
+ const uint8* s = src_ptr;
+ const uint8* t = src_ptr + src_stride;
+ int x;
+ assert((dst_width % 3 == 0) && (dst_width > 0));
+ for (x = 0; x < dst_width; x += 3) {
+ uint8 a0 = (s[0] * 3 + s[1] * 1 + 2) >> 2;
+ uint8 a1 = (s[1] * 1 + s[2] * 1 + 1) >> 1;
+ uint8 a2 = (s[2] * 1 + s[3] * 3 + 2) >> 2;
+ uint8 b0 = (t[0] * 3 + t[1] * 1 + 2) >> 2;
+ uint8 b1 = (t[1] * 1 + t[2] * 1 + 1) >> 1;
+ uint8 b2 = (t[2] * 1 + t[3] * 3 + 2) >> 2;
+ d[0] = (a0 * 3 + b0 + 2) >> 2;
+ d[1] = (a1 * 3 + b1 + 2) >> 2;
+ d[2] = (a2 * 3 + b2 + 2) >> 2;
+ d += 3;
+ s += 4;
+ t += 4;
+ }
+}
+
+void ScaleRowDown34_0_Box_16_C(const uint16* src_ptr, ptrdiff_t src_stride,
+ uint16* d, int dst_width) {
+ const uint16* s = src_ptr;
+ const uint16* t = src_ptr + src_stride;
+ int x;
+ assert((dst_width % 3 == 0) && (dst_width > 0));
+ for (x = 0; x < dst_width; x += 3) {
+ uint16 a0 = (s[0] * 3 + s[1] * 1 + 2) >> 2;
+ uint16 a1 = (s[1] * 1 + s[2] * 1 + 1) >> 1;
+ uint16 a2 = (s[2] * 1 + s[3] * 3 + 2) >> 2;
+ uint16 b0 = (t[0] * 3 + t[1] * 1 + 2) >> 2;
+ uint16 b1 = (t[1] * 1 + t[2] * 1 + 1) >> 1;
+ uint16 b2 = (t[2] * 1 + t[3] * 3 + 2) >> 2;
+ d[0] = (a0 * 3 + b0 + 2) >> 2;
+ d[1] = (a1 * 3 + b1 + 2) >> 2;
+ d[2] = (a2 * 3 + b2 + 2) >> 2;
+ d += 3;
+ s += 4;
+ t += 4;
+ }
+}
+
+// Filter rows 1 and 2 together, 1 : 1
+void ScaleRowDown34_1_Box_C(const uint8* src_ptr, ptrdiff_t src_stride,
+ uint8* d, int dst_width) {
+ const uint8* s = src_ptr;
+ const uint8* t = src_ptr + src_stride;
+ int x;
+ assert((dst_width % 3 == 0) && (dst_width > 0));
+ for (x = 0; x < dst_width; x += 3) {
+ uint8 a0 = (s[0] * 3 + s[1] * 1 + 2) >> 2;
+ uint8 a1 = (s[1] * 1 + s[2] * 1 + 1) >> 1;
+ uint8 a2 = (s[2] * 1 + s[3] * 3 + 2) >> 2;
+ uint8 b0 = (t[0] * 3 + t[1] * 1 + 2) >> 2;
+ uint8 b1 = (t[1] * 1 + t[2] * 1 + 1) >> 1;
+ uint8 b2 = (t[2] * 1 + t[3] * 3 + 2) >> 2;
+ d[0] = (a0 + b0 + 1) >> 1;
+ d[1] = (a1 + b1 + 1) >> 1;
+ d[2] = (a2 + b2 + 1) >> 1;
+ d += 3;
+ s += 4;
+ t += 4;
+ }
+}
+
+void ScaleRowDown34_1_Box_16_C(const uint16* src_ptr, ptrdiff_t src_stride,
+ uint16* d, int dst_width) {
+ const uint16* s = src_ptr;
+ const uint16* t = src_ptr + src_stride;
+ int x;
+ assert((dst_width % 3 == 0) && (dst_width > 0));
+ for (x = 0; x < dst_width; x += 3) {
+ uint16 a0 = (s[0] * 3 + s[1] * 1 + 2) >> 2;
+ uint16 a1 = (s[1] * 1 + s[2] * 1 + 1) >> 1;
+ uint16 a2 = (s[2] * 1 + s[3] * 3 + 2) >> 2;
+ uint16 b0 = (t[0] * 3 + t[1] * 1 + 2) >> 2;
+ uint16 b1 = (t[1] * 1 + t[2] * 1 + 1) >> 1;
+ uint16 b2 = (t[2] * 1 + t[3] * 3 + 2) >> 2;
+ d[0] = (a0 + b0 + 1) >> 1;
+ d[1] = (a1 + b1 + 1) >> 1;
+ d[2] = (a2 + b2 + 1) >> 1;
+ d += 3;
+ s += 4;
+ t += 4;
+ }
+}
+
+// Scales a single row of pixels using point sampling.
+void ScaleCols_C(uint8* dst_ptr, const uint8* src_ptr,
+ int dst_width, int x, int dx) {
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ dst_ptr[0] = src_ptr[x >> 16];
+ x += dx;
+ dst_ptr[1] = src_ptr[x >> 16];
+ x += dx;
+ dst_ptr += 2;
+ }
+ if (dst_width & 1) {
+ dst_ptr[0] = src_ptr[x >> 16];
+ }
+}
+
+void ScaleCols_16_C(uint16* dst_ptr, const uint16* src_ptr,
+ int dst_width, int x, int dx) {
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ dst_ptr[0] = src_ptr[x >> 16];
+ x += dx;
+ dst_ptr[1] = src_ptr[x >> 16];
+ x += dx;
+ dst_ptr += 2;
+ }
+ if (dst_width & 1) {
+ dst_ptr[0] = src_ptr[x >> 16];
+ }
+}
+
+// Scales a single row of pixels up by 2x using point sampling.
+void ScaleColsUp2_C(uint8* dst_ptr, const uint8* src_ptr,
+ int dst_width, int x, int dx) {
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ dst_ptr[1] = dst_ptr[0] = src_ptr[0];
+ src_ptr += 1;
+ dst_ptr += 2;
+ }
+ if (dst_width & 1) {
+ dst_ptr[0] = src_ptr[0];
+ }
+}
+
+void ScaleColsUp2_16_C(uint16* dst_ptr, const uint16* src_ptr,
+ int dst_width, int x, int dx) {
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ dst_ptr[1] = dst_ptr[0] = src_ptr[0];
+ src_ptr += 1;
+ dst_ptr += 2;
+ }
+ if (dst_width & 1) {
+ dst_ptr[0] = src_ptr[0];
+ }
+}
+
+// (1-f)a + fb can be replaced with a + f(b-a)
+#if defined(__arm__) || defined(__aarch64__)
+#define BLENDER(a, b, f) (uint8)((int)(a) + \
+ ((((int)((f)) * ((int)(b) - (int)(a))) + 0x8000) >> 16))
+#else
+// inteluses 7 bit math with rounding.
+#define BLENDER(a, b, f) (uint8)((int)(a) + \
+ (((int)((f) >> 9) * ((int)(b) - (int)(a)) + 0x40) >> 7))
+#endif
+
+void ScaleFilterCols_C(uint8* dst_ptr, const uint8* src_ptr,
+ int dst_width, int x, int dx) {
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ int xi = x >> 16;
+ int a = src_ptr[xi];
+ int b = src_ptr[xi + 1];
+ dst_ptr[0] = BLENDER(a, b, x & 0xffff);
+ x += dx;
+ xi = x >> 16;
+ a = src_ptr[xi];
+ b = src_ptr[xi + 1];
+ dst_ptr[1] = BLENDER(a, b, x & 0xffff);
+ x += dx;
+ dst_ptr += 2;
+ }
+ if (dst_width & 1) {
+ int xi = x >> 16;
+ int a = src_ptr[xi];
+ int b = src_ptr[xi + 1];
+ dst_ptr[0] = BLENDER(a, b, x & 0xffff);
+ }
+}
+
+void ScaleFilterCols64_C(uint8* dst_ptr, const uint8* src_ptr,
+ int dst_width, int x32, int dx) {
+ int64 x = (int64)(x32);
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ int64 xi = x >> 16;
+ int a = src_ptr[xi];
+ int b = src_ptr[xi + 1];
+ dst_ptr[0] = BLENDER(a, b, x & 0xffff);
+ x += dx;
+ xi = x >> 16;
+ a = src_ptr[xi];
+ b = src_ptr[xi + 1];
+ dst_ptr[1] = BLENDER(a, b, x & 0xffff);
+ x += dx;
+ dst_ptr += 2;
+ }
+ if (dst_width & 1) {
+ int64 xi = x >> 16;
+ int a = src_ptr[xi];
+ int b = src_ptr[xi + 1];
+ dst_ptr[0] = BLENDER(a, b, x & 0xffff);
+ }
+}
+#undef BLENDER
+
+// Same as 8 bit arm blender but return is cast to uint16
+#define BLENDER(a, b, f) (uint16)((int)(a) + \
+ ((((int)((f)) * ((int)(b) - (int)(a))) + 0x8000) >> 16))
+
+void ScaleFilterCols_16_C(uint16* dst_ptr, const uint16* src_ptr,
+ int dst_width, int x, int dx) {
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ int xi = x >> 16;
+ int a = src_ptr[xi];
+ int b = src_ptr[xi + 1];
+ dst_ptr[0] = BLENDER(a, b, x & 0xffff);
+ x += dx;
+ xi = x >> 16;
+ a = src_ptr[xi];
+ b = src_ptr[xi + 1];
+ dst_ptr[1] = BLENDER(a, b, x & 0xffff);
+ x += dx;
+ dst_ptr += 2;
+ }
+ if (dst_width & 1) {
+ int xi = x >> 16;
+ int a = src_ptr[xi];
+ int b = src_ptr[xi + 1];
+ dst_ptr[0] = BLENDER(a, b, x & 0xffff);
+ }
+}
+
+void ScaleFilterCols64_16_C(uint16* dst_ptr, const uint16* src_ptr,
+ int dst_width, int x32, int dx) {
+ int64 x = (int64)(x32);
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ int64 xi = x >> 16;
+ int a = src_ptr[xi];
+ int b = src_ptr[xi + 1];
+ dst_ptr[0] = BLENDER(a, b, x & 0xffff);
+ x += dx;
+ xi = x >> 16;
+ a = src_ptr[xi];
+ b = src_ptr[xi + 1];
+ dst_ptr[1] = BLENDER(a, b, x & 0xffff);
+ x += dx;
+ dst_ptr += 2;
+ }
+ if (dst_width & 1) {
+ int64 xi = x >> 16;
+ int a = src_ptr[xi];
+ int b = src_ptr[xi + 1];
+ dst_ptr[0] = BLENDER(a, b, x & 0xffff);
+ }
+}
+#undef BLENDER
+
+void ScaleRowDown38_C(const uint8* src_ptr, ptrdiff_t src_stride,
+ uint8* dst, int dst_width) {
+ int x;
+ assert(dst_width % 3 == 0);
+ for (x = 0; x < dst_width; x += 3) {
+ dst[0] = src_ptr[0];
+ dst[1] = src_ptr[3];
+ dst[2] = src_ptr[6];
+ dst += 3;
+ src_ptr += 8;
+ }
+}
+
+void ScaleRowDown38_16_C(const uint16* src_ptr, ptrdiff_t src_stride,
+ uint16* dst, int dst_width) {
+ int x;
+ assert(dst_width % 3 == 0);
+ for (x = 0; x < dst_width; x += 3) {
+ dst[0] = src_ptr[0];
+ dst[1] = src_ptr[3];
+ dst[2] = src_ptr[6];
+ dst += 3;
+ src_ptr += 8;
+ }
+}
+
+// 8x3 -> 3x1
+void ScaleRowDown38_3_Box_C(const uint8* src_ptr,
+ ptrdiff_t src_stride,
+ uint8* dst_ptr, int dst_width) {
+ intptr_t stride = src_stride;
+ int i;
+ assert((dst_width % 3 == 0) && (dst_width > 0));
+ for (i = 0; i < dst_width; i += 3) {
+ dst_ptr[0] = (src_ptr[0] + src_ptr[1] + src_ptr[2] +
+ src_ptr[stride + 0] + src_ptr[stride + 1] +
+ src_ptr[stride + 2] + src_ptr[stride * 2 + 0] +
+ src_ptr[stride * 2 + 1] + src_ptr[stride * 2 + 2]) *
+ (65536 / 9) >> 16;
+ dst_ptr[1] = (src_ptr[3] + src_ptr[4] + src_ptr[5] +
+ src_ptr[stride + 3] + src_ptr[stride + 4] +
+ src_ptr[stride + 5] + src_ptr[stride * 2 + 3] +
+ src_ptr[stride * 2 + 4] + src_ptr[stride * 2 + 5]) *
+ (65536 / 9) >> 16;
+ dst_ptr[2] = (src_ptr[6] + src_ptr[7] +
+ src_ptr[stride + 6] + src_ptr[stride + 7] +
+ src_ptr[stride * 2 + 6] + src_ptr[stride * 2 + 7]) *
+ (65536 / 6) >> 16;
+ src_ptr += 8;
+ dst_ptr += 3;
+ }
+}
+
+void ScaleRowDown38_3_Box_16_C(const uint16* src_ptr,
+ ptrdiff_t src_stride,
+ uint16* dst_ptr, int dst_width) {
+ intptr_t stride = src_stride;
+ int i;
+ assert((dst_width % 3 == 0) && (dst_width > 0));
+ for (i = 0; i < dst_width; i += 3) {
+ dst_ptr[0] = (src_ptr[0] + src_ptr[1] + src_ptr[2] +
+ src_ptr[stride + 0] + src_ptr[stride + 1] +
+ src_ptr[stride + 2] + src_ptr[stride * 2 + 0] +
+ src_ptr[stride * 2 + 1] + src_ptr[stride * 2 + 2]) *
+ (65536 / 9) >> 16;
+ dst_ptr[1] = (src_ptr[3] + src_ptr[4] + src_ptr[5] +
+ src_ptr[stride + 3] + src_ptr[stride + 4] +
+ src_ptr[stride + 5] + src_ptr[stride * 2 + 3] +
+ src_ptr[stride * 2 + 4] + src_ptr[stride * 2 + 5]) *
+ (65536 / 9) >> 16;
+ dst_ptr[2] = (src_ptr[6] + src_ptr[7] +
+ src_ptr[stride + 6] + src_ptr[stride + 7] +
+ src_ptr[stride * 2 + 6] + src_ptr[stride * 2 + 7]) *
+ (65536 / 6) >> 16;
+ src_ptr += 8;
+ dst_ptr += 3;
+ }
+}
+
+// 8x2 -> 3x1
+void ScaleRowDown38_2_Box_C(const uint8* src_ptr, ptrdiff_t src_stride,
+ uint8* dst_ptr, int dst_width) {
+ intptr_t stride = src_stride;
+ int i;
+ assert((dst_width % 3 == 0) && (dst_width > 0));
+ for (i = 0; i < dst_width; i += 3) {
+ dst_ptr[0] = (src_ptr[0] + src_ptr[1] + src_ptr[2] +
+ src_ptr[stride + 0] + src_ptr[stride + 1] +
+ src_ptr[stride + 2]) * (65536 / 6) >> 16;
+ dst_ptr[1] = (src_ptr[3] + src_ptr[4] + src_ptr[5] +
+ src_ptr[stride + 3] + src_ptr[stride + 4] +
+ src_ptr[stride + 5]) * (65536 / 6) >> 16;
+ dst_ptr[2] = (src_ptr[6] + src_ptr[7] +
+ src_ptr[stride + 6] + src_ptr[stride + 7]) *
+ (65536 / 4) >> 16;
+ src_ptr += 8;
+ dst_ptr += 3;
+ }
+}
+
+void ScaleRowDown38_2_Box_16_C(const uint16* src_ptr, ptrdiff_t src_stride,
+ uint16* dst_ptr, int dst_width) {
+ intptr_t stride = src_stride;
+ int i;
+ assert((dst_width % 3 == 0) && (dst_width > 0));
+ for (i = 0; i < dst_width; i += 3) {
+ dst_ptr[0] = (src_ptr[0] + src_ptr[1] + src_ptr[2] +
+ src_ptr[stride + 0] + src_ptr[stride + 1] +
+ src_ptr[stride + 2]) * (65536 / 6) >> 16;
+ dst_ptr[1] = (src_ptr[3] + src_ptr[4] + src_ptr[5] +
+ src_ptr[stride + 3] + src_ptr[stride + 4] +
+ src_ptr[stride + 5]) * (65536 / 6) >> 16;
+ dst_ptr[2] = (src_ptr[6] + src_ptr[7] +
+ src_ptr[stride + 6] + src_ptr[stride + 7]) *
+ (65536 / 4) >> 16;
+ src_ptr += 8;
+ dst_ptr += 3;
+ }
+}
+
+void ScaleAddRow_C(const uint8* src_ptr, uint16* dst_ptr, int src_width) {
+ int x;
+ assert(src_width > 0);
+ for (x = 0; x < src_width - 1; x += 2) {
+ dst_ptr[0] += src_ptr[0];
+ dst_ptr[1] += src_ptr[1];
+ src_ptr += 2;
+ dst_ptr += 2;
+ }
+ if (src_width & 1) {
+ dst_ptr[0] += src_ptr[0];
+ }
+}
+
+void ScaleAddRow_16_C(const uint16* src_ptr, uint32* dst_ptr, int src_width) {
+ int x;
+ assert(src_width > 0);
+ for (x = 0; x < src_width - 1; x += 2) {
+ dst_ptr[0] += src_ptr[0];
+ dst_ptr[1] += src_ptr[1];
+ src_ptr += 2;
+ dst_ptr += 2;
+ }
+ if (src_width & 1) {
+ dst_ptr[0] += src_ptr[0];
+ }
+}
+
+void ScaleARGBRowDown2_C(const uint8* src_argb,
+ ptrdiff_t src_stride,
+ uint8* dst_argb, int dst_width) {
+ const uint32* src = (const uint32*)(src_argb);
+ uint32* dst = (uint32*)(dst_argb);
+
+ int x;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = src[1];
+ dst[1] = src[3];
+ src += 4;
+ dst += 2;
+ }
+ if (dst_width & 1) {
+ dst[0] = src[1];
+ }
+}
+
+void ScaleARGBRowDown2Linear_C(const uint8* src_argb,
+ ptrdiff_t src_stride,
+ uint8* dst_argb, int dst_width) {
+ int x;
+ for (x = 0; x < dst_width; ++x) {
+ dst_argb[0] = (src_argb[0] + src_argb[4] + 1) >> 1;
+ dst_argb[1] = (src_argb[1] + src_argb[5] + 1) >> 1;
+ dst_argb[2] = (src_argb[2] + src_argb[6] + 1) >> 1;
+ dst_argb[3] = (src_argb[3] + src_argb[7] + 1) >> 1;
+ src_argb += 8;
+ dst_argb += 4;
+ }
+}
+
+void ScaleARGBRowDown2Box_C(const uint8* src_argb, ptrdiff_t src_stride,
+ uint8* dst_argb, int dst_width) {
+ int x;
+ for (x = 0; x < dst_width; ++x) {
+ dst_argb[0] = (src_argb[0] + src_argb[4] +
+ src_argb[src_stride] + src_argb[src_stride + 4] + 2) >> 2;
+ dst_argb[1] = (src_argb[1] + src_argb[5] +
+ src_argb[src_stride + 1] + src_argb[src_stride + 5] + 2) >> 2;
+ dst_argb[2] = (src_argb[2] + src_argb[6] +
+ src_argb[src_stride + 2] + src_argb[src_stride + 6] + 2) >> 2;
+ dst_argb[3] = (src_argb[3] + src_argb[7] +
+ src_argb[src_stride + 3] + src_argb[src_stride + 7] + 2) >> 2;
+ src_argb += 8;
+ dst_argb += 4;
+ }
+}
+
+void ScaleARGBRowDownEven_C(const uint8* src_argb, ptrdiff_t src_stride,
+ int src_stepx,
+ uint8* dst_argb, int dst_width) {
+ const uint32* src = (const uint32*)(src_argb);
+ uint32* dst = (uint32*)(dst_argb);
+
+ int x;
+ for (x = 0; x < dst_width - 1; x += 2) {
+ dst[0] = src[0];
+ dst[1] = src[src_stepx];
+ src += src_stepx * 2;
+ dst += 2;
+ }
+ if (dst_width & 1) {
+ dst[0] = src[0];
+ }
+}
+
+void ScaleARGBRowDownEvenBox_C(const uint8* src_argb,
+ ptrdiff_t src_stride,
+ int src_stepx,
+ uint8* dst_argb, int dst_width) {
+ int x;
+ for (x = 0; x < dst_width; ++x) {
+ dst_argb[0] = (src_argb[0] + src_argb[4] +
+ src_argb[src_stride] + src_argb[src_stride + 4] + 2) >> 2;
+ dst_argb[1] = (src_argb[1] + src_argb[5] +
+ src_argb[src_stride + 1] + src_argb[src_stride + 5] + 2) >> 2;
+ dst_argb[2] = (src_argb[2] + src_argb[6] +
+ src_argb[src_stride + 2] + src_argb[src_stride + 6] + 2) >> 2;
+ dst_argb[3] = (src_argb[3] + src_argb[7] +
+ src_argb[src_stride + 3] + src_argb[src_stride + 7] + 2) >> 2;
+ src_argb += src_stepx * 4;
+ dst_argb += 4;
+ }
+}
+
+// Scales a single row of pixels using point sampling.
+void ScaleARGBCols_C(uint8* dst_argb, const uint8* src_argb,
+ int dst_width, int x, int dx) {
+ const uint32* src = (const uint32*)(src_argb);
+ uint32* dst = (uint32*)(dst_argb);
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ dst[0] = src[x >> 16];
+ x += dx;
+ dst[1] = src[x >> 16];
+ x += dx;
+ dst += 2;
+ }
+ if (dst_width & 1) {
+ dst[0] = src[x >> 16];
+ }
+}
+
+void ScaleARGBCols64_C(uint8* dst_argb, const uint8* src_argb,
+ int dst_width, int x32, int dx) {
+ int64 x = (int64)(x32);
+ const uint32* src = (const uint32*)(src_argb);
+ uint32* dst = (uint32*)(dst_argb);
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ dst[0] = src[x >> 16];
+ x += dx;
+ dst[1] = src[x >> 16];
+ x += dx;
+ dst += 2;
+ }
+ if (dst_width & 1) {
+ dst[0] = src[x >> 16];
+ }
+}
+
+// Scales a single row of pixels up by 2x using point sampling.
+void ScaleARGBColsUp2_C(uint8* dst_argb, const uint8* src_argb,
+ int dst_width, int x, int dx) {
+ const uint32* src = (const uint32*)(src_argb);
+ uint32* dst = (uint32*)(dst_argb);
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ dst[1] = dst[0] = src[0];
+ src += 1;
+ dst += 2;
+ }
+ if (dst_width & 1) {
+ dst[0] = src[0];
+ }
+}
+
+// TODO(fbarchard): Replace 0x7f ^ f with 128-f. bug=607.
+// Mimics SSSE3 blender
+#define BLENDER1(a, b, f) ((a) * (0x7f ^ f) + (b) * f) >> 7
+#define BLENDERC(a, b, f, s) (uint32)( \
+ BLENDER1(((a) >> s) & 255, ((b) >> s) & 255, f) << s)
+#define BLENDER(a, b, f) \
+ BLENDERC(a, b, f, 24) | BLENDERC(a, b, f, 16) | \
+ BLENDERC(a, b, f, 8) | BLENDERC(a, b, f, 0)
+
+void ScaleARGBFilterCols_C(uint8* dst_argb, const uint8* src_argb,
+ int dst_width, int x, int dx) {
+ const uint32* src = (const uint32*)(src_argb);
+ uint32* dst = (uint32*)(dst_argb);
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ int xi = x >> 16;
+ int xf = (x >> 9) & 0x7f;
+ uint32 a = src[xi];
+ uint32 b = src[xi + 1];
+ dst[0] = BLENDER(a, b, xf);
+ x += dx;
+ xi = x >> 16;
+ xf = (x >> 9) & 0x7f;
+ a = src[xi];
+ b = src[xi + 1];
+ dst[1] = BLENDER(a, b, xf);
+ x += dx;
+ dst += 2;
+ }
+ if (dst_width & 1) {
+ int xi = x >> 16;
+ int xf = (x >> 9) & 0x7f;
+ uint32 a = src[xi];
+ uint32 b = src[xi + 1];
+ dst[0] = BLENDER(a, b, xf);
+ }
+}
+
+void ScaleARGBFilterCols64_C(uint8* dst_argb, const uint8* src_argb,
+ int dst_width, int x32, int dx) {
+ int64 x = (int64)(x32);
+ const uint32* src = (const uint32*)(src_argb);
+ uint32* dst = (uint32*)(dst_argb);
+ int j;
+ for (j = 0; j < dst_width - 1; j += 2) {
+ int64 xi = x >> 16;
+ int xf = (x >> 9) & 0x7f;
+ uint32 a = src[xi];
+ uint32 b = src[xi + 1];
+ dst[0] = BLENDER(a, b, xf);
+ x += dx;
+ xi = x >> 16;
+ xf = (x >> 9) & 0x7f;
+ a = src[xi];
+ b = src[xi + 1];
+ dst[1] = BLENDER(a, b, xf);
+ x += dx;
+ dst += 2;
+ }
+ if (dst_width & 1) {
+ int64 xi = x >> 16;
+ int xf = (x >> 9) & 0x7f;
+ uint32 a = src[xi];
+ uint32 b = src[xi + 1];
+ dst[0] = BLENDER(a, b, xf);
+ }
+}
+#undef BLENDER1
+#undef BLENDERC
+#undef BLENDER
+
+// Scale plane vertically with bilinear interpolation.
+void ScalePlaneVertical(int src_height,
+ int dst_width, int dst_height,
+ int src_stride, int dst_stride,
+ const uint8* src_argb, uint8* dst_argb,
+ int x, int y, int dy,
+ int bpp, enum FilterMode filtering) {
+ // TODO(fbarchard): Allow higher bpp.
+ int dst_width_bytes = dst_width * bpp;
+ void (*InterpolateRow)(uint8* dst_argb, const uint8* src_argb,
+ ptrdiff_t src_stride, int dst_width, int source_y_fraction) =
+ InterpolateRow_C;
+ const int max_y = (src_height > 1) ? ((src_height - 1) << 16) - 1 : 0;
+ int j;
+ assert(bpp >= 1 && bpp <= 4);
+ assert(src_height != 0);
+ assert(dst_width > 0);
+ assert(dst_height > 0);
+ src_argb += (x >> 16) * bpp;
+#if defined(HAS_INTERPOLATEROW_SSSE3)
+ if (TestCpuFlag(kCpuHasSSSE3)) {
+ InterpolateRow = InterpolateRow_Any_SSSE3;
+ if (IS_ALIGNED(dst_width_bytes, 16)) {
+ InterpolateRow = InterpolateRow_SSSE3;
+ }
+ }
+#endif
+#if defined(HAS_INTERPOLATEROW_AVX2)
+ if (TestCpuFlag(kCpuHasAVX2)) {
+ InterpolateRow = InterpolateRow_Any_AVX2;
+ if (IS_ALIGNED(dst_width_bytes, 32)) {
+ InterpolateRow = InterpolateRow_AVX2;
+ }
+ }
+#endif
+#if defined(HAS_INTERPOLATEROW_NEON)
+ if (TestCpuFlag(kCpuHasNEON)) {
+ InterpolateRow = InterpolateRow_Any_NEON;
+ if (IS_ALIGNED(dst_width_bytes, 16)) {
+ InterpolateRow = InterpolateRow_NEON;
+ }
+ }
+#endif
+#if defined(HAS_INTERPOLATEROW_DSPR2)
+ if (TestCpuFlag(kCpuHasDSPR2) &&
+ IS_ALIGNED(src_argb, 4) && IS_ALIGNED(src_stride, 4) &&
+ IS_ALIGNED(dst_argb, 4) && IS_ALIGNED(dst_stride, 4)) {
+ InterpolateRow = InterpolateRow_Any_DSPR2;
+ if (IS_ALIGNED(dst_width_bytes, 4)) {
+ InterpolateRow = InterpolateRow_DSPR2;
+ }
+ }
+#endif
+ for (j = 0; j < dst_height; ++j) {
+ int yi;
+ int yf;
+ if (y > max_y) {
+ y = max_y;
+ }
+ yi = y >> 16;
+ yf = filtering ? ((y >> 8) & 255) : 0;
+ InterpolateRow(dst_argb, src_argb + yi * src_stride,
+ src_stride, dst_width_bytes, yf);
+ dst_argb += dst_stride;
+ y += dy;
+ }
+}
+void ScalePlaneVertical_16(int src_height,
+ int dst_width, int dst_height,
+ int src_stride, int dst_stride,
+ const uint16* src_argb, uint16* dst_argb,
+ int x, int y, int dy,
+ int wpp, enum FilterMode filtering) {
+ // TODO(fbarchard): Allow higher wpp.
+ int dst_width_words = dst_width * wpp;
+ void (*InterpolateRow)(uint16* dst_argb, const uint16* src_argb,
+ ptrdiff_t src_stride, int dst_width, int source_y_fraction) =
+ InterpolateRow_16_C;
+ const int max_y = (src_height > 1) ? ((src_height - 1) << 16) - 1 : 0;
+ int j;
+ assert(wpp >= 1 && wpp <= 2);
+ assert(src_height != 0);
+ assert(dst_width > 0);
+ assert(dst_height > 0);
+ src_argb += (x >> 16) * wpp;
+#if defined(HAS_INTERPOLATEROW_16_SSE2)
+ if (TestCpuFlag(kCpuHasSSE2)) {
+ InterpolateRow = InterpolateRow_Any_16_SSE2;
+ if (IS_ALIGNED(dst_width_bytes, 16)) {
+ InterpolateRow = InterpolateRow_16_SSE2;
+ }
+ }
+#endif
+#if defined(HAS_INTERPOLATEROW_16_SSSE3)
+ if (TestCpuFlag(kCpuHasSSSE3)) {
+ InterpolateRow = InterpolateRow_Any_16_SSSE3;
+ if (IS_ALIGNED(dst_width_bytes, 16)) {
+ InterpolateRow = InterpolateRow_16_SSSE3;
+ }
+ }
+#endif
+#if defined(HAS_INTERPOLATEROW_16_AVX2)
+ if (TestCpuFlag(kCpuHasAVX2)) {
+ InterpolateRow = InterpolateRow_Any_16_AVX2;
+ if (IS_ALIGNED(dst_width_bytes, 32)) {
+ InterpolateRow = InterpolateRow_16_AVX2;
+ }
+ }
+#endif
+#if defined(HAS_INTERPOLATEROW_16_NEON)
+ if (TestCpuFlag(kCpuHasNEON)) {
+ InterpolateRow = InterpolateRow_Any_16_NEON;
+ if (IS_ALIGNED(dst_width_bytes, 16)) {
+ InterpolateRow = InterpolateRow_16_NEON;
+ }
+ }
+#endif
+#if defined(HAS_INTERPOLATEROW_16_DSPR2)
+ if (TestCpuFlag(kCpuHasDSPR2) &&
+ IS_ALIGNED(src_argb, 4) && IS_ALIGNED(src_stride, 4) &&
+ IS_ALIGNED(dst_argb, 4) && IS_ALIGNED(dst_stride, 4)) {
+ InterpolateRow = InterpolateRow_Any_16_DSPR2;
+ if (IS_ALIGNED(dst_width_bytes, 4)) {
+ InterpolateRow = InterpolateRow_16_DSPR2;
+ }
+ }
+#endif
+ for (j = 0; j < dst_height; ++j) {
+ int yi;
+ int yf;
+ if (y > max_y) {
+ y = max_y;
+ }
+ yi = y >> 16;
+ yf = filtering ? ((y >> 8) & 255) : 0;
+ InterpolateRow(dst_argb, src_argb + yi * src_stride,
+ src_stride, dst_width_words, yf);
+ dst_argb += dst_stride;
+ y += dy;
+ }
+}
+
+// Simplify the filtering based on scale factors.
+enum FilterMode ScaleFilterReduce(int src_width, int src_height,
+ int dst_width, int dst_height,
+ enum FilterMode filtering) {
+ if (src_width < 0) {
+ src_width = -src_width;
+ }
+ if (src_height < 0) {
+ src_height = -src_height;
+ }
+ if (filtering == kFilterBox) {
+ // If scaling both axis to 0.5 or larger, switch from Box to Bilinear.
+ if (dst_width * 2 >= src_width && dst_height * 2 >= src_height) {
+ filtering = kFilterBilinear;
+ }
+ }
+ if (filtering == kFilterBilinear) {
+ if (src_height == 1) {
+ filtering = kFilterLinear;
+ }
+ // TODO(fbarchard): Detect any odd scale factor and reduce to Linear.
+ if (dst_height == src_height || dst_height * 3 == src_height) {
+ filtering = kFilterLinear;
+ }
+ // TODO(fbarchard): Remove 1 pixel wide filter restriction, which is to
+ // avoid reading 2 pixels horizontally that causes memory exception.
+ if (src_width == 1) {
+ filtering = kFilterNone;
+ }
+ }
+ if (filtering == kFilterLinear) {
+ if (src_width == 1) {
+ filtering = kFilterNone;
+ }
+ // TODO(fbarchard): Detect any odd scale factor and reduce to None.
+ if (dst_width == src_width || dst_width * 3 == src_width) {
+ filtering = kFilterNone;
+ }
+ }
+ return filtering;
+}
+
+// Divide num by div and return as 16.16 fixed point result.
+int FixedDiv_C(int num, int div) {
+ return (int)(((int64)(num) << 16) / div);
+}
+
+// Divide num by div and return as 16.16 fixed point result.
+int FixedDiv1_C(int num, int div) {
+ return (int)((((int64)(num) << 16) - 0x00010001) /
+ (div - 1));
+}
+
+#define CENTERSTART(dx, s) (dx < 0) ? -((-dx >> 1) + s) : ((dx >> 1) + s)
+
+// Compute slope values for stepping.
+void ScaleSlope(int src_width, int src_height,
+ int dst_width, int dst_height,
+ enum FilterMode filtering,
+ int* x, int* y, int* dx, int* dy) {
+ assert(x != NULL);
+ assert(y != NULL);
+ assert(dx != NULL);
+ assert(dy != NULL);
+ assert(src_width != 0);
+ assert(src_height != 0);
+ assert(dst_width > 0);
+ assert(dst_height > 0);
+ // Check for 1 pixel and avoid FixedDiv overflow.
+ if (dst_width == 1 && src_width >= 32768) {
+ dst_width = src_width;
+ }
+ if (dst_height == 1 && src_height >= 32768) {
+ dst_height = src_height;
+ }
+ if (filtering == kFilterBox) {
+ // Scale step for point sampling duplicates all pixels equally.
+ *dx = FixedDiv(Abs(src_width), dst_width);
+ *dy = FixedDiv(src_height, dst_height);
+ *x = 0;
+ *y = 0;
+ } else if (filtering == kFilterBilinear) {
+ // Scale step for bilinear sampling renders last pixel once for upsample.
+ if (dst_width <= Abs(src_width)) {
+ *dx = FixedDiv(Abs(src_width), dst_width);
+ *x = CENTERSTART(*dx, -32768); // Subtract 0.5 (32768) to center filter.
+ } else if (dst_width > 1) {
+ *dx = FixedDiv1(Abs(src_width), dst_width);
+ *x = 0;
+ }
+ if (dst_height <= src_height) {
+ *dy = FixedDiv(src_height, dst_height);
+ *y = CENTERSTART(*dy, -32768); // Subtract 0.5 (32768) to center filter.
+ } else if (dst_height > 1) {
+ *dy = FixedDiv1(src_height, dst_height);
+ *y = 0;
+ }
+ } else if (filtering == kFilterLinear) {
+ // Scale step for bilinear sampling renders last pixel once for upsample.
+ if (dst_width <= Abs(src_width)) {
+ *dx = FixedDiv(Abs(src_width), dst_width);
+ *x = CENTERSTART(*dx, -32768); // Subtract 0.5 (32768) to center filter.
+ } else if (dst_width > 1) {
+ *dx = FixedDiv1(Abs(src_width), dst_width);
+ *x = 0;
+ }
+ *dy = FixedDiv(src_height, dst_height);
+ *y = *dy >> 1;
+ } else {
+ // Scale step for point sampling duplicates all pixels equally.
+ *dx = FixedDiv(Abs(src_width), dst_width);
+ *dy = FixedDiv(src_height, dst_height);
+ *x = CENTERSTART(*dx, 0);
+ *y = CENTERSTART(*dy, 0);
+ }
+ // Negative src_width means horizontally mirror.
+ if (src_width < 0) {
+ *x += (dst_width - 1) * *dx;
+ *dx = -*dx;
+ // src_width = -src_width; // Caller must do this.
+ }
+}
+#undef CENTERSTART
+
+#ifdef __cplusplus
+} // extern "C"
+} // namespace libyuv
+#endif