Get rid of UNSAFE_TODOs in ARGB to 8 BPP CompositeRow functions
Convert CompositeRow_AlphaToMask() and CompositeRow_Argb2Gray() using
Zip() and color structs.
Bug: 42271176
Change-Id: Ie2347b6659d5b313e620f1d1b06bb006071422be
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/123076
Reviewed-by: Tom Sepez <tsepez@google.com>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fxge/dib/cfx_scanlinecompositor.cpp b/core/fxge/dib/cfx_scanlinecompositor.cpp
index 9473107..f7ab405 100644
--- a/core/fxge/dib/cfx_scanlinecompositor.cpp
+++ b/core/fxge/dib/cfx_scanlinecompositor.cpp
@@ -154,28 +154,34 @@
output.red = FXDIB_ALPHA_MERGE(input.red, output.red, alpha);
}
-void CompositeRow_AlphaToMask(pdfium::span<uint8_t> dest_span,
- pdfium::span<const uint8_t> src_span,
- int pixel_count,
- pdfium::span<const uint8_t> clip_span,
- uint8_t stride) {
- uint8_t* dest_scan = dest_span.data();
- const uint8_t* src_scan = src_span.data();
- const uint8_t* clip_scan = clip_span.data();
- UNSAFE_TODO({
- src_scan += stride - 1;
- for (int col = 0; col < pixel_count; ++col) {
- int src_alpha = GetAlpha(*src_scan, clip_scan, col);
- uint8_t back_alpha = *dest_scan;
- if (!back_alpha) {
- *dest_scan = src_alpha;
- } else if (src_alpha) {
- *dest_scan = back_alpha + src_alpha - back_alpha * src_alpha / 255;
- }
- ++dest_scan;
- src_scan += stride;
+void CompositePixelArgb2Mask(const FX_BGRA_STRUCT<uint8_t>& input,
+ uint8_t clip,
+ uint8_t& output) {
+ const uint8_t src_alpha = input.alpha * clip / 255;
+ if (output == 0) {
+ output = src_alpha;
+ return;
+ }
+ if (src_alpha == 0) {
+ return;
+ }
+ output = FXDIB_ALPHA_UNION(output, src_alpha);
+}
+
+void CompositeRowArgb2Mask(pdfium::span<const FX_BGRA_STRUCT<uint8_t>> src_span,
+ pdfium::span<const uint8_t> clip_span,
+ pdfium::span<uint8_t> dest_span) {
+ if (clip_span.empty()) {
+ for (auto [input, output] : fxcrt::Zip(src_span, dest_span)) {
+ CompositePixelArgb2Mask(input, /*clip=*/255, output);
}
- });
+ return;
+ }
+
+ for (auto [input, clip, output] :
+ fxcrt::Zip(src_span, clip_span, dest_span)) {
+ CompositePixelArgb2Mask(input, clip, output);
+ }
}
void CompositeRow_Rgb2Mask(pdfium::span<uint8_t> dest_span,
@@ -208,41 +214,48 @@
}
}
-uint8_t GetGray(const uint8_t* src_scan) {
- return UNSAFE_TODO(FXRGB2GRAY(src_scan[2], src_scan[1], *src_scan));
-}
-
-uint8_t GetGrayWithBlend(const uint8_t* src_scan,
- const uint8_t* dest_scan,
+template <typename T>
+uint8_t GetGrayWithBlend(const T& input,
+ uint8_t output_value,
BlendMode blend_type) {
- uint8_t gray = GetGray(src_scan);
- if (IsNonSeparableBlendMode(blend_type))
- gray = blend_type == BlendMode::kLuminosity ? gray : *dest_scan;
- else if (blend_type != BlendMode::kNormal)
- gray = Blend(blend_type, *dest_scan, gray);
+ uint8_t gray = FXRGB2GRAY(input.red, input.green, input.blue);
+ if (IsNonSeparableBlendMode(blend_type)) {
+ return blend_type == BlendMode::kLuminosity ? gray : output_value;
+ }
+ if (blend_type != BlendMode::kNormal) {
+ return Blend(blend_type, output_value, gray);
+ }
return gray;
}
-void CompositeRow_Argb2Gray(pdfium::span<uint8_t> dest_span,
- pdfium::span<const uint8_t> src_span,
- int pixel_count,
- BlendMode blend_type,
- pdfium::span<const uint8_t> clip_span) {
- uint8_t* dest_scan = dest_span.data();
- const uint8_t* src_scan = src_span.data();
- const uint8_t* clip_scan = clip_span.data();
- constexpr size_t kOffset = 4;
- UNSAFE_TODO({
- for (int col = 0; col < pixel_count; ++col) {
- int src_alpha = GetAlpha(src_scan[3], clip_scan, col);
- if (src_alpha) {
- uint8_t gray = GetGrayWithBlend(src_scan, dest_scan, blend_type);
- *dest_scan = FXDIB_ALPHA_MERGE(*dest_scan, gray, src_alpha);
- }
- ++dest_scan;
- src_scan += kOffset;
+void CompositePixelArgb2Gray(const FX_BGRA_STRUCT<uint8_t>& input,
+ uint8_t clip,
+ uint8_t& output,
+ BlendMode blend_type) {
+ const uint8_t src_alpha = input.alpha * clip / 255;
+ if (src_alpha == 0) {
+ return;
+ }
+
+ uint8_t gray = GetGrayWithBlend(input, output, blend_type);
+ output = FXDIB_ALPHA_MERGE(output, gray, src_alpha);
+}
+
+void CompositeRowArgb2Gray(pdfium::span<const FX_BGRA_STRUCT<uint8_t>> src_span,
+ pdfium::span<const uint8_t> clip_span,
+ pdfium::span<uint8_t> dest_span,
+ BlendMode blend_type) {
+ if (clip_span.empty()) {
+ for (auto [input, output] : fxcrt::Zip(src_span, dest_span)) {
+ CompositePixelArgb2Gray(input, /*clip=*/255, output, blend_type);
}
- });
+ return;
+ }
+
+ for (auto [input, clip, output] :
+ fxcrt::Zip(src_span, clip_span, dest_span)) {
+ CompositePixelArgb2Gray(input, clip, output, blend_type);
+ }
}
void CompositeRow_Rgb2Gray(pdfium::span<uint8_t> dest_span,
@@ -256,7 +269,9 @@
const uint8_t* clip_scan = clip_span.data();
UNSAFE_TODO({
for (int col = 0; col < pixel_count; ++col) {
- uint8_t gray = GetGrayWithBlend(src_scan, dest_scan, blend_type);
+ FX_BGR_STRUCT input = {
+ .blue = src_scan[0], .green = src_scan[1], .red = src_scan[2]};
+ uint8_t gray = GetGrayWithBlend(input, *dest_scan, blend_type);
if (clip_scan && clip_scan[col] < 255) {
*dest_scan = FXDIB_ALPHA_MERGE(*dest_scan, gray, clip_scan[col]);
} else {
@@ -2401,6 +2416,10 @@
pdfium::span<const uint8_t> clip_scan) const {
CHECK_EQ(m_SrcFormat, FXDIB_Format::kArgb);
+ auto src_span =
+ fxcrt::reinterpret_span<const FX_BGRA_STRUCT<uint8_t>>(src_scan).first(
+ width);
+
switch (m_DestFormat) {
case FXDIB_Format::kInvalid:
case FXDIB_Format::k1bppRgb:
@@ -2409,19 +2428,15 @@
}
case FXDIB_Format::k8bppRgb: {
CHECK(!m_bRgbByteOrder); // Disallowed by Init();
- CompositeRow_Argb2Gray(dest_scan, src_scan, width, m_BlendType,
- clip_scan);
+ CompositeRowArgb2Gray(src_span, clip_scan, dest_scan, m_BlendType);
return;
}
case FXDIB_Format::k8bppMask: {
CHECK(!m_bRgbByteOrder); // Disallowed by Init();
- CompositeRow_AlphaToMask(dest_scan, src_scan, width, clip_scan, 4);
+ CompositeRowArgb2Mask(src_span, clip_scan, dest_scan);
return;
}
case FXDIB_Format::kRgb: {
- auto src_span =
- fxcrt::reinterpret_span<const FX_BGRA_STRUCT<uint8_t>>(src_scan)
- .first(width);
if (m_bRgbByteOrder) {
auto dest_span =
fxcrt::reinterpret_span<FX_RGB_STRUCT<uint8_t>>(dest_scan);
@@ -2435,9 +2450,6 @@
return;
}
case FXDIB_Format::kRgb32: {
- auto src_span =
- fxcrt::reinterpret_span<const FX_BGRA_STRUCT<uint8_t>>(src_scan)
- .first(width);
if (m_bRgbByteOrder) {
auto dest_span =
fxcrt::reinterpret_span<FX_RGBA_STRUCT<uint8_t>>(dest_scan);
@@ -2451,9 +2463,6 @@
return;
}
case FXDIB_Format::kArgb: {
- auto src_span =
- fxcrt::reinterpret_span<const FX_BGRA_STRUCT<uint8_t>>(src_scan)
- .first(width);
if (m_bRgbByteOrder) {
auto dest_span =
fxcrt::reinterpret_span<FX_RGBA_STRUCT<uint8_t>>(dest_scan);
