diff options
Diffstat (limited to 'services/surfaceflinger/RegionSamplingThread.cpp')
| -rw-r--r-- | services/surfaceflinger/RegionSamplingThread.cpp | 35 |
1 files changed, 9 insertions, 26 deletions
diff --git a/services/surfaceflinger/RegionSamplingThread.cpp b/services/surfaceflinger/RegionSamplingThread.cpp index 1c1367c916..b7e772d917 100644 --- a/services/surfaceflinger/RegionSamplingThread.cpp +++ b/services/surfaceflinger/RegionSamplingThread.cpp @@ -268,16 +268,6 @@ void RegionSamplingThread::binderDied(const wp<IBinder>& who) { mDescriptors.erase(who); } -namespace { -// Using Rec. 709 primaries -inline float getLuma(float r, float g, float b) { - constexpr auto rec709_red_primary = 0.2126f; - constexpr auto rec709_green_primary = 0.7152f; - constexpr auto rec709_blue_primary = 0.0722f; - return rec709_red_primary * r + rec709_green_primary * g + rec709_blue_primary * b; -} -} // anonymous namespace - float sampleArea(const uint32_t* data, int32_t width, int32_t height, int32_t stride, uint32_t orientation, const Rect& sample_area) { if (!sample_area.isValid() || (sample_area.getWidth() > width) || @@ -298,30 +288,23 @@ float sampleArea(const uint32_t* data, int32_t width, int32_t height, int32_t st std::swap(area.left, area.right); } - std::array<int32_t, 256> brightnessBuckets = {}; - const int32_t majoritySampleNum = area.getWidth() * area.getHeight() / 2; + const uint32_t pixelCount = (area.bottom - area.top) * (area.right - area.left); + uint32_t accumulatedLuma = 0; + // Calculates luma with approximation of Rec. 709 primaries for (int32_t row = area.top; row < area.bottom; ++row) { const uint32_t* rowBase = data + row * stride; for (int32_t column = area.left; column < area.right; ++column) { uint32_t pixel = rowBase[column]; - const float r = pixel & 0xFF; - const float g = (pixel >> 8) & 0xFF; - const float b = (pixel >> 16) & 0xFF; - const uint8_t luma = std::round(getLuma(r, g, b)); - ++brightnessBuckets[luma]; - if (brightnessBuckets[luma] > majoritySampleNum) return luma / 255.0f; + const uint32_t r = pixel & 0xFF; + const uint32_t g = (pixel >> 8) & 0xFF; + const uint32_t b = (pixel >> 16) & 0xFF; + const uint32_t luma = (r * 7 + b * 2 + g * 23) >> 5; + accumulatedLuma += luma; } } - int32_t accumulated = 0; - size_t bucket = 0; - for (; bucket < brightnessBuckets.size(); bucket++) { - accumulated += brightnessBuckets[bucket]; - if (accumulated > majoritySampleNum) break; - } - - return bucket / 255.0f; + return accumulatedLuma / (255.0f * pixelCount); } std::vector<float> RegionSamplingThread::sampleBuffer( |