[PDF Ink Signatures] Make ink::Brush in PdfInkBrush mutable

Make ink::Brush in PdfInkBrush mutable and provide SetColor() and
SetSize() methods to change the brush parameters. This will be used in
future CL https://crrev.com/c/5932590, so that a new PdfInkBrush does
not have to be created every time the brush changes.

Bug: 373672165
Change-Id: Ib8be7c5c0da454fa8c1715153007965a8bc94ca7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5932589
Reviewed-by: Lei Zhang <thestig@chromium.org>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Commit-Queue: Andy Phan <andyphan@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1370361}

pdf/pdf_ink_brush.cc

@@ -43,6 +43,17 @@ float GetOpacity(PdfInkBrush::Type type) {
   NOTREACHED();
 }
 
+// ink::Brush actually uses ink::Color, but pdf/ uses SkColor. To avoid having
+// multiple color representations, do not expose ink::Color and just convert
+// `color`.
+ink::Color GetInkColorFromSkColor(SkColor color) {
+  return ink::Color::FromUint8(
+      /*red=*/SkColorGetR(color),
+      /*green=*/SkColorGetG(color),
+      /*blue=*/SkColorGetB(color),
+      /*alpha=*/SkColorGetA(color));
+}
+
 ink::Brush CreateInkBrush(PdfInkBrush::Type type, SkColor color, float size) {
   CHECK(PdfInkBrush::IsToolSizeInRange(size));
 
@@ -56,16 +67,9 @@ ink::Brush CreateInkBrush(PdfInkBrush::Type type, SkColor color, float size) {
                                          /*uri_string=*/"");
   CHECK(family.ok());
 
-  // ink::Brush actually uses ink::Color, but pdf/ uses SkColor. To avoid having
-  // multiple color representations, do not expose ink::Color and just convert
-  // `color`.
   auto brush = ink::Brush::Create(*family,
                                   /*color=*/
-                                  ink::Color::FromUint8(
-                                      /*red=*/SkColorGetR(color),
-                                      /*green=*/SkColorGetG(color),
-                                      /*blue=*/SkColorGetB(color),
-                                      /*alpha=*/SkColorGetA(color)),
+                                  GetInkColorFromSkColor(color),
                                   /*size=*/size,
                                   /*epsilon=*/0.1f);
   CHECK(brush.ok());
@@ -118,4 +122,13 @@ gfx::Rect PdfInkBrush::GetInvalidateArea(const gfx::PointF& center1,
   return area2;
 }
 
+void PdfInkBrush::SetColor(SkColor color) {
+  ink_brush_.SetColor(GetInkColorFromSkColor(color));
+}
+
+void PdfInkBrush::SetSize(float size) {
+  auto size_result = ink_brush_.SetSize(std::move(size));
+  CHECK(size_result.ok());
+}
+
 }  // namespace chrome_pdf

pdf/pdf_ink_brush.h

@@ -49,9 +49,12 @@ class PdfInkBrush {
 
   const ink::Brush& ink_brush() const { return ink_brush_; }
 
+  void SetColor(SkColor color);
+
+  void SetSize(float size);
+
  private:
-  // The Ink brush initialized based on the PdfInkBrush ctor parameters.
-  const ink::Brush ink_brush_;
+  ink::Brush ink_brush_;
 };
 
 }  // namespace chrome_pdf

pdf/pdf_ink_brush_unittest.cc

@@ -6,6 +6,7 @@
 
 #include <memory>
 
+#include "pdf/pdf_ink_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/geometry/point_f.h"
@@ -45,4 +46,20 @@ TEST(PdfInkBrushTest, InvalidateDifferentPoints) {
                                      gfx::PointF(15.0f, 32.0f)));
 }
 
+TEST(PdfInkBrushTest, SetColor) {
+  auto brush = CreatePdfInkBrush(/*size=*/10.0f);
+  EXPECT_EQ(SK_ColorBLACK, GetSkColorFromInkBrush(brush->ink_brush()));
+
+  brush->SetColor(SK_ColorCYAN);
+  EXPECT_EQ(SK_ColorCYAN, GetSkColorFromInkBrush(brush->ink_brush()));
+}
+
+TEST(PdfInkBrushTest, SetSize) {
+  auto brush = CreatePdfInkBrush(/*size=*/10.0f);
+  EXPECT_EQ(10.0f, brush->ink_brush().GetSize());
+
+  brush->SetSize(4.0f);
+  EXPECT_EQ(4.0f, brush->ink_brush().GetSize());
+}
+
 }  // namespace chrome_pdf