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Android: Add support for cropping textures

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BUG=b/28622232
R=glaznev@webrtc.org, nisse@webrtc.org

Review URL: https://codereview.webrtc.org/1965953003 .

Cr-Commit-Position: refs/heads/master@{#12720}
This commit is contained in:
Magnus Jedvert
2016-05-13 12:51:04 +02:00
parent 834a6ea12b
commit a3002db8d6
4 changed files with 57 additions and 17 deletions
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51
webrtc/api/java/jni/native_handle_impl.cc
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@ -59,6 +59,37 @@ void RotateMatrix(float a[16], webrtc::VideoRotation rotation) {
}
}
// Calculates result = a * b, in column-major order.
void MultiplyMatrix(const float a[16], const float b[16], float result[16]) {
for (int i = 0; i < 4; ++i) {
for (int j = 0; j < 4; ++j) {
float sum = 0;
for (int k = 0; k < 4; ++k) {
sum += a[k * 4 + j] * b[i * 4 + k];
}
result[i * 4 + j] = sum;
}
}
}
// Center crop by keeping xFraction of the width and yFraction of the height,
// so e.g. cropping from 640x480 to 640x360 would use
// xFraction=1, yFraction=360/480.
void CropMatrix(float a[16], float xFraction, float yFraction) {
// Move cropped area to the center of the frame by offsetting half the
// removed area.
const float xOffset = (1 - xFraction) / 2;
const float yOffset = (1 - yFraction) / 2;
const float crop_matrix[16] = {
xFraction, 0, 0, 0,
0, yFraction, 0, 0,
0, 0, 1, 0,
xOffset, yOffset, 0, 1};
float mul_result[16];
MultiplyMatrix(crop_matrix, a, mul_result);
memcpy(a, mul_result, sizeof(mul_result));
}
} // anonymouse namespace
namespace webrtc_jni {
@ -146,15 +177,18 @@ AndroidTextureBuffer::NativeToI420Buffer() {
}
rtc::scoped_refptr<AndroidTextureBuffer>
AndroidTextureBuffer::ScaleAndRotate(int dst_widht,
int dst_height,
webrtc::VideoRotation rotation) {
if (width() == dst_widht && height() == dst_height &&
AndroidTextureBuffer::CropScaleAndRotate(int cropped_width,
int cropped_height,
int dst_width,
int dst_height,
webrtc::VideoRotation rotation) {
if (cropped_width == dst_width && cropped_height == dst_height &&
width() == dst_width && height() == dst_height &&
rotation == webrtc::kVideoRotation_0) {
return this;
}
int rotated_width = (rotation % 180 == 0) ? dst_widht : dst_height;
int rotated_height = (rotation % 180 == 0) ? dst_height : dst_widht;
int rotated_width = (rotation % 180 == 0) ? dst_width : dst_height;
int rotated_height = (rotation % 180 == 0) ? dst_height : dst_width;
// Here we use Bind magic to add a reference count to |this| until the newly
// created AndroidTextureBuffer is destructed
@ -163,6 +197,11 @@ AndroidTextureBuffer::ScaleAndRotate(int dst_widht,
rotated_width, rotated_height, native_handle_,
surface_texture_helper_, rtc::KeepRefUntilDone(this)));
if (cropped_width != width() || cropped_height != height()) {
CropMatrix(buffer->native_handle_.sampling_matrix,
cropped_width / static_cast<float>(width()),
cropped_height / static_cast<float>(height()));
}
RotateMatrix(buffer->native_handle_.sampling_matrix, rotation);
return buffer;
}