-
-
Notifications
You must be signed in to change notification settings - Fork 184
/
Copy pathDownscaler.cpp
301 lines (245 loc) · 9.97 KB
/
Downscaler.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
10000
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "Downscaler.h"
#include <algorithm>
#include <ctime>
#include "mozilla/gfx/2D.h"
using std::swap;
namespace mozilla {
using gfx::IntRect;
namespace image {
Downscaler::Downscaler(const nsIntSize& aTargetSize)
: mTargetSize(aTargetSize),
mOutputBuffer(nullptr),
mWindowCapacity(0),
mLinesInBuffer(0),
mPrevInvalidatedLine(0),
mCurrentOutLine(0),
mCurrentInLine(0),
mHasAlpha(true),
mFlipVertically(false) {
MOZ_ASSERT(mTargetSize.width > 0 && mTargetSize.height > 0,
"Invalid target size");
}
Downscaler::~Downscaler() { ReleaseWindow(); }
void Downscaler::ReleaseWindow() {
if (!mWindow) {
return;
}
for (int32_t i = 0; i < mWindowCapacity; ++i) {
delete[] mWindow[i];
}
mWindow = nullptr;
mWindowCapacity = 0;
}
nsresult Downscaler::BeginFrame(const nsIntSize& aOriginalSize,
const Maybe<nsIntRect>& aFrameRect,
uint8_t* aOutputBuffer, bool aHasAlpha,
bool aFlipVertically /* = false */) {
MOZ_ASSERT(aOutputBuffer);
MOZ_ASSERT(mTargetSize != aOriginalSize,
"Created a downscaler, but not downscaling?");
MOZ_ASSERT(mTargetSize.width <= aOriginalSize.width,
"Created a downscaler, but width is larger");
MOZ_ASSERT(mTargetSize.height <= aOriginalSize.height,
"Created a downscaler, but height is larger");
MOZ_ASSERT(aOriginalSize.width > 0 && aOriginalSize.height > 0,
"Invalid original size");
// Only downscale from reasonable sizes to avoid using too much memory/cpu
// downscaling and decoding. 1 << 20 == 1,048,576 seems a reasonable limit.
if (aOriginalSize.width > (1 << 20) || aOriginalSize.height > (1 << 20)) {
NS_WARNING("Trying to downscale image frame that is too large");
return NS_ERROR_INVALID_ARG;
}
mFrameRect = aFrameRect.valueOr(nsIntRect(nsIntPoint(), aOriginalSize));
MOZ_ASSERT(mFrameRect.X() >= 0 && mFrameRect.Y() >= 0 &&
mFrameRect.Width() >= 0 && mFrameRect.Height() >= 0,
"Frame rect must have non-negative components");
MOZ_ASSERT(nsIntRect(0, 0, aOriginalSize.width, aOriginalSize.height)
.Contains(mFrameRect),
"Frame rect must fit inside image");
MOZ_ASSERT_IF(!nsIntRect(0, 0, aOriginalSize.width, aOriginalSize.height)
.IsEqualEdges(mFrameRect),
aHasAlpha);
mOriginalSize = aOriginalSize;
mScale = gfx::MatrixScalesDouble(
double(mOriginalSize.width) / mTargetSize.width,
double(mOriginalSize.height) / mTargetSize.height);
mOutputBuffer = aOutputBuffer;
mHasAlpha = aHasAlpha;
mFlipVertically = aFlipVertically;
ReleaseWindow();
auto resizeMethod = gfx::ConvolutionFilter::ResizeMethod::LANCZOS3;
if (!mXFilter.ComputeResizeFilter(resizeMethod, mOriginalSize.width,
mTargetSize.width) ||
!mYFilter.ComputeResizeFilter(resizeMethod, mOriginalSize.height,
mTargetSize.height)) {
NS_WARNING("Failed to compute filters for image downscaling");
return NS_ERROR_OUT_OF_MEMORY;
}
// Allocate the buffer, which contains scanlines of the original image.
// pad to handle overreads by the simd code
size_t bufferLen = gfx::ConvolutionFilter::PadBytesForSIMD(
mOriginalSize.width * sizeof(uint32_t));
mRowBuffer.reset(new (fallible) uint8_t[bufferLen]);
if (MOZ_UNLIKELY(!mRowBuffer)) {
return NS_ERROR_OUT_OF_MEMORY;
}
// Zero buffer to keep valgrind happy.
memset(mRowBuffer.get(), 0, bufferLen);
// Allocate the window, which contains horizontally downscaled scanlines. (We
// can store scanlines which are already downscale because our downscaling
// filter is separable.)
mWindowCapacity = mYFilter.MaxFilter();
mWindow.reset(new (fallible) uint8_t*[mWindowCapacity]);
if (MOZ_UNLIKELY(!mWindow)) {
return NS_ERROR_OUT_OF_MEMORY;
}
bool anyAllocationFailed = false;
// pad to handle overreads by the simd code
const size_t rowSize = gfx::ConvolutionFilter::PadBytesForSIMD(
mTargetSize.width * sizeof(uint32_t));
for (int32_t i = 0; i < mWindowCapacity; ++i) {
mWindow[i] = new (fallible) uint8_t[rowSize];
anyAllocationFailed = anyAllocationFailed || mWindow[i] == nullptr;
}
if (MOZ_UNLIKELY(anyAllocationFailed)) {
// We intentionally iterate through the entire array even if an allocation
// fails, to ensure that all the pointers in it are either valid or nullptr.
// That in turn ensures that ReleaseWindow() can clean up correctly.
return NS_ERROR_OUT_OF_MEMORY;
}
ResetForNextProgressivePass();
return NS_OK;
}
void Downscaler::SkipToRow(int32_t aRow) {
if (mCurrentInLine < aRow) {
ClearRow();
do {
CommitRow();
} while (mCurrentInLine < aRow);
}
}
void Downscaler::ResetForNextProgressivePass() {
mPrevInvalidatedLine = 0;
mCurrentOutLine = 0;
mCurrentInLine = 0;
mLinesInBuffer = 0;
if (mFrameRect.IsEmpty()) {
// Our frame rect is zero size; commit rows until the end of the image.
SkipToRow(mOriginalSize.height - 1);
} else {
// If we have a vertical offset, commit rows to shift us past it.
SkipToRow(mFrameRect.Y());
}
}
void Downscaler::ClearRestOfRow(uint32_t aStartingAtCol) {
MOZ_ASSERT(int64_t(aStartingAtCol) <= int64_t(mOriginalSize.width));
uint32_t bytesToClear =
(mOriginalSize.width - aStartingAtCol) * sizeof(uint32_t);
memset(mRowBuffer.get() + (aStartingAtCol * sizeof(uint32_t)), 0,
bytesToClear);
}
void Downscaler::CommitRow() {
MOZ_ASSERT(mOutputBuffer, "Should have a current frame");
MOZ_ASSERT(mCurrentInLine < mOriginalSize.height, "Past end of input");
if (mCurrentOutLine < mTargetSize.height) {
int32_t filterOffset = 0;
int32_t filterLength = 0;
mYFilter.GetFilterOffsetAndLength(mCurrentOutLine, &filterOffset,
&filterLength);
int32_t inLineToRead = filterOffset + mLinesInBuffer;
MOZ_ASSERT(mCurrentInLine <= inLineToRead, "Reading past end of input");
if (mCurrentInLine == inLineToRead) {
MOZ_RELEASE_ASSERT(mLinesInBuffer < mWindowCapacity,
"Need more rows than capacity!");
mXFilter.ConvolveHorizontally(mRowBuffer.get(), mWindow[mLinesInBuffer++],
mHasAlpha);
}
MOZ_ASSERT(mCurrentOutLine < mTargetSize.height,
"Writing past end of output");
while (mLinesInBuffer >= filterLength) {
DownscaleInputLine();
if (mCurrentOutLine == mTargetSize.height) {
break; // We're done.
}
mYFilter.GetFilterOffsetAndLength(mCurrentOutLine, &filterOffset,
&filterLength);
}
}
mCurrentInLine += 1;
// If we're at the end of the part of the original image that has data, commit
// rows to shift us to the end.
if (mCurrentInLine == (mFrameRect.Y() + mFrameRect.Height())) {
SkipToRow(mOriginalSize.height - 1);
}
}
bool Downscaler::HasInvalidation() const {
return mCurrentOutLine > mPrevInvalidatedLine;
}
DownscalerInvalidRect Downscaler::TakeInvalidRect() {
if (MOZ_UNLIKELY(!HasInvalidation())) {
return DownscalerInvalidRect();
}
DownscalerInvalidRect invalidRect;
// Compute the target size invalid rect.
if (mFlipVertically) {
// We need to flip it. This will implicitly flip the original size invalid
// rect, since we compute it by scaling this rect.
invalidRect.mTargetSizeRect =
IntRect(0, mTargetSize.height - mCurrentOutLine, mTargetSize.width,
mCurrentOutLine - mPrevInvalidatedLine);
} else {
invalidRect.mTargetSizeRect =
IntRect(0, mPrevInvalidatedLine, mTargetSize.width,
mCurrentOutLine - mPrevInvalidatedLine);
}
mPrevInvalidatedLine = mCurrentOutLine;
// Compute the original size invalid rect.
invalidRect.mOriginalSizeRect = invalidRect.mTargetSizeRect;
invalidRect.mOriginalSizeRect.ScaleRoundOut(mScale.xScale, mScale.yScale);
return invalidRect;
}
void Downscaler::DownscaleInputLine() {
MOZ_ASSERT(mOutputBuffer);
MOZ_ASSERT(mCurrentOutLine < mTargetSize.height,
"Writing past end of output");
int32_t filterOffset = 0;
int32_t filterLength = 0;
mYFilter.GetFilterOffsetAndLength(mCurrentOutLine, &filterOffset,
&filterLength);
int32_t currentOutLine = mFlipVertically
? mTargetSize.height - (mCurrentOutLine + 1)
: mCurrentOutLine;
MOZ_ASSERT(currentOutLine >= 0);
uint8_t* outputLine =
&mOutputBuffer[currentOutLine * mTargetSize.width * sizeof(uint32_t)];
mYFilter.ConvolveVertically(mWindow.get(), outputLine, mCurrentOutLine,
mXFilter.NumValues(), mHasAlpha);
mCurrentOutLine += 1;
if (mCurrentOutLine == mTargetSize.height) {
// We're done.
return;
}
int32_t newFilterOffset = 0;
int32_t newFilterLength = 0;
mYFilter.GetFilterOffsetAndLength(mCurrentOutLine, &newFilterOffset,
&newFilterLength);
int diff = newFilterOffset - filterOffset;
MOZ_ASSERT(diff >= 0, "Moving backwards in the filter?");
// Shift the buffer. We're just moving pointers here, so this is cheap.
mLinesInBuffer -= diff;
mLinesInBuffer = std::min(std::max(mLinesInBuffer, 0), mWindowCapacity);
// If we already have enough rows to satisfy the filter, there is no need
// to swap as we won't be writing more before the next convolution.
if (filterLength > mLinesInBuffer) {
for (int32_t i = 0; i < mLinesInBuffer; ++i) {
swap(mWindow[i], mWindow[filterLength - mLinesInBuffer + i]);
}
}
}
} // namespace image
} // namespace mozilla