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Commit ff831abf authored by Daniel Norman's avatar Daniel Norman
Browse files

fix(edt): Exclude barcodes from inversion in force invert 

Detects barcodes using a simple heuristic based on black and white pixel
count, then for any detected barcode image: the image is *not* inverted
and a white border is drawn around the image to provide the "quiet zone"
necessary for most barcode scanners to recognize the barcode.

Bug: 411725862
Test: atest RenderNodeDrawable
Test: Use in various apps that provide barcodes and QR codes, observe
      barcodes are not inverted and other images are unaffected.
Test: Repeat using automated app crawl tests
Flag: android.view.accessibility.force_invert_color
Change-Id: I83e5302e18c69c01fd67f2ff0ca0f6e3abbdb75e
parent 8a414be0

libs/hwui/CanvasTransform.cpp

+8 −5
Original line number Diff line number Diff line
@@ -143,7 +143,8 @@ static BitmapPalette paletteForColorHSV(SkColor color) { 
}



BitmapPalette filterPalette(const SkPaint* paint, BitmapPalette palette) {

    if (palette == BitmapPalette::Unknown || !paint || !paint->getColorFilter()) {

    if ((palette != BitmapPalette::Light && palette != BitmapPalette::Dark) || !paint ||

        !paint->getColorFilter()) {

        return palette;

    }
@@ -161,11 +162,13 @@ bool transformPaint(ColorTransform transform, SkPaint* paint) { 


bool transformPaint(ColorTransform transform, SkPaint* paint, BitmapPalette palette) {

    bool shouldInvert = false;

    if (transform == ColorTransform::Invert && palette != BitmapPalette::Colorful) {

        // When the transform is Invert we invert any image that is not deemed "colorful",

        // regardless of calculated image brightness.

    if (transform == ColorTransform::Invert) {

        if (palette != BitmapPalette::Barcode && palette != BitmapPalette::Colorful) {

            // When the transform is Invert we invert any image that is not deemed "colorful"

            // or a barcode, regardless of calculated image brightness.

            shouldInvert = true;

        }

    }

    palette = filterPalette(paint, palette);

    if (palette == BitmapPalette::Light && transform == ColorTransform::Dark) {

        shouldInvert = true;

libs/hwui/ColorArea.cpp

+1 −0
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ void ColorArea::addArea(const SkRect& bounds, const SkPaint& paint, 
            addArea(area, Dark);

            break;

        case android::BitmapPalette::Colorful:

        case android::BitmapPalette::Barcode:

        case android::BitmapPalette::Unknown:

            addArea(area, Unknown);

            break;

libs/hwui/RecordingCanvas.cpp

+14 −2
Original line number Diff line number Diff line
@@ -104,6 +104,8 @@ enum class Type : uint8_t { 
};

#undef X



static constexpr uint32_t BARCODE_QUIET_ZONE_PX = 5;



struct Op {

    uint32_t type : 8;

    uint32_t skip : 24;
@@ -491,13 +493,23 @@ struct DrawImageRect final : Op { 
        if (ATRACE_ENABLED()) {

            traceBitmapScaling(c, image, src, dst);

        }

        SkRect destination = dst;

        if (CC_UNLIKELY(palette == BitmapPalette::Barcode)) {

            // Draw an extra quiet zone around the bitmap in order to guarantee that there

            // is a white border between the likely-black background and the black portion of

            // the barcode.

            SkPaint whitePaint;

            whitePaint.setColor(SkColors::kWhite);

            c->drawRect(destination, whitePaint);

            destination.inset(BARCODE_QUIET_ZONE_PX, BARCODE_QUIET_ZONE_PX);

        }

        if (gainmap) {

            DrawGainmapBitmap(c, image, src, dst, sampling, &paint, constraint, gainmap,

            DrawGainmapBitmap(c, image, src, destination, sampling, &paint, constraint, gainmap,

                              gainmapInfo);

        } else {

            SkPaint newPaint = paint;

            tonemapPaint(image->imageInfo(), c->imageInfo(), -1, newPaint);

            c->drawImageRect(image.get(), src, dst, sampling, &newPaint, constraint);

            c->drawImageRect(image.get(), src, destination, sampling, &newPaint, constraint);

        }

    }

libs/hwui/hwui/Bitmap.cpp

+37 −1
Original line number Diff line number Diff line
@@ -525,6 +525,24 @@ private: 
    int mCount = 0;

};



template <int N>

class Histogram {

public:

    // Expects values between 0f and 1f

    void add(float sample) {

        if (sample >= 0.f && sample <= 1.f) {

            buckets[std::min(N - 1, static_cast<int>(sample * N))]++;

        }

    }



    int size() { return N; }



    int operator[](int i) const { return buckets[i]; }



private:

    std::array<int, N> buckets;

};



BitmapPalette Bitmap::computePalette(const SkImageInfo& info, const void* addr, size_t rowBytes) {

    ATRACE_CALL();
@@ -536,6 +554,7 @@ BitmapPalette Bitmap::computePalette(const SkImageInfo& info, const void* addr, 


    MinMaxAverage hue, saturation, value;

    int sampledCount = 0;

    Histogram<10> valueHistogram;



    // Sample a grid of 100 pixels to get an overall estimation of the colors in play

    const int x_step = std::max(1, pixmap.width() / 10);
@@ -552,7 +571,9 @@ BitmapPalette Bitmap::computePalette(const SkImageInfo& info, const void* addr, 
            SkColorToHSV(color, hsv);

            hue.add(hsv[0]);

            saturation.add(hsv[1]);

            value.add(hsv[2]);

            float val = hsv[2];

            value.add(val);

            valueHistogram.add(val);

        }

    }
@@ -570,6 +591,21 @@ BitmapPalette Bitmap::computePalette(const SkImageInfo& info, const void* addr, 
          saturation.average(), info.width(), info.height());



    if (CC_UNLIKELY(view_accessibility_flags::force_invert_color())) {

        // The following palettes only apply when the app is applying Force Invert and are not

        // used by classic Force Dark.

        // TODO: b/411725862 - Improve the barcode heuristic by incorporating actual barcode specs

        if (sampledCount > 80) {

            // The image should be majority pure black and white, but not entirely one color.

            int expectedBlackAndWhiteSamples = sampledCount * 0.9;

            int expectedBlackOrWhiteSamples = sampledCount * 0.25;

            int blackSamples = valueHistogram[0];

            int whiteSamples = valueHistogram[valueHistogram.size() - 1];

            if (blackSamples + whiteSamples >= expectedBlackAndWhiteSamples &&

                blackSamples >= expectedBlackOrWhiteSamples &&

                whiteSamples >= expectedBlackOrWhiteSamples) {

                return BitmapPalette::Barcode;

            }

        }

        if (saturation.delta() > 0.1f ||

            (hue.delta() > 20 && saturation.average() > 0.2f && value.average() < 0.9f)) {

            return BitmapPalette::Colorful;

libs/hwui/hwui/Bitmap.h

+6 −0
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ enum class BitmapPalette { 
    Light,

    Dark,

    Colorful,

    Barcode,

};



namespace uirenderer {
@@ -171,6 +172,11 @@ public: 
        return mPalette;

    }



    void setPalette(BitmapPalette palette) {

        mPalette = palette;

        mPaletteGenerationId = getGenerationID();

    }



  // returns true if rowBytes * height can be represented by a positive int32_t value

  // and places that value in size.

  static bool computeAllocationSize(size_t rowBytes, int height, size_t* size);