SkPdf: smaller color serialization

SkPDFUtils now has a special function (SkPDFUtils::AppendColorComponent)
just for writing out (color/255) as a decimal with three digits of
precision.

SkPDFUnion now has a type to represent a color component.  It holds a
utint_8, but calls into AppendColorComponent to serialize.

Added a unit test that tests all possible input values.
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2151863003

Review-Url: https://codereview.chromium.org/2151863003

1 files changed, 16 insertions, 0 deletions

diff --git a/bench/PDFBench.cpp b/bench/PDFBench.cpp
index 8f5d2db5b4..19f8e2f8cd 100644
--- a/bench/PDFBench.cpp
+++ b/bench/PDFBench.cpp
@@ -164,6 +164,21 @@ struct PDFScalarBench : public Benchmark {
     }
 };
 
+struct PDFColorComponentBench : public Benchmark {
+    bool isSuitableFor(Backend b) override {
+        return b == kNonRendering_Backend;
+    }
+    const char* onGetName() override { return "PDFColorComponent"; }
+    void onDraw(int loops, SkCanvas*) override {
+        char dst[5];
+        while (loops-- > 0) {
+            for (int i = 0; i < 256; ++i) {
+                (void)SkPDFUtils::ColorToDecimal(SkToU8(i), dst);
+            }
+        }
+    }
+};
+
 struct PDFShaderBench : public Benchmark {
     sk_sp<SkShader> fShader;
     const char* onGetName() final { return "PDFShader"; }
@@ -232,6 +247,7 @@ DEF_BENCH(return new PDFImageBench;)
 DEF_BENCH(return new PDFJpegImageBench;)
 DEF_BENCH(return new PDFCompressionBench;)
 DEF_BENCH(return new PDFScalarBench;)
+DEF_BENCH(return new PDFColorComponentBench;)
 DEF_BENCH(return new PDFShaderBench;)
 DEF_BENCH(return new WStreamWriteTextBenchmark;)
 DEF_BENCH(return new WritePDFTextBenchmark;)