[core] Make Image safer

Provide Image::copy, which handles copying rectangles from a source to a destination, with thorough bounds checking.

Also fixes an indexing error in SpriteAtlas, where the top row of pixels in a wrapped image was copied from the wrong source row.

2 files changed, 10 insertions, 13 deletions

diff --git a/test/text/glyph_atlas.test.cpp b/test/text/glyph_atlas.test.cpp
index e229cd117b..1ad2af9d82 100644
--- a/test/text/glyph_atlas.test.cpp
+++ b/test/text/glyph_atlas.test.cpp
@@ -145,16 +145,12 @@ TEST(GlyphAtlas, LoadingCancel) {
 
 TEST(GlyphAtlas, InvalidSDFGlyph) {
     GlyphSet glyphSet;
-    glyphSet.insert(65, SDFGlyph{ 65 /* ASCII 'A' */,
-                                  "x" /* bitmap is too short */,
-                                  { 1 /* width */, 1 /* height */, 0 /* left */, 0 /* top */,
-                                    0 /* advance */ } });
     glyphSet.insert(66, SDFGlyph{ 66 /* ASCII 'B' */,
-                                  std::string(7 * 7, 'x'), /* correct */
+                                  AlphaImage({7, 7}), /* correct */
                                   { 1 /* width */, 1 /* height */, 0 /* left */, 0 /* top */,
                                     0 /* advance */ } });
     glyphSet.insert(67, SDFGlyph{ 67 /* ASCII 'C' */,
-                                  std::string(518 * 8, 'x'), /* correct */
+                                  AlphaImage({518, 8}), /* correct */
                                   { 512 /* width */, 2 /* height */, 0 /* left */, 0 /* top */,
                                     0 /* advance */ } });
 
@@ -165,11 +161,10 @@ TEST(GlyphAtlas, InvalidSDFGlyph) {
     GlyphPositions positions;
     test.glyphAtlas.addGlyphs(1, std::u16string{u"ABC"}, fontStack, glyphSet, positions);
 
-    ASSERT_EQ(3u, positions.size());
+    ASSERT_EQ(2u, positions.size());
 
-    // 'A' was not placed because the bitmap size is invalid.
-    ASSERT_NE(positions.end(), positions.find(65));
-    ASSERT_EQ((Rect<uint16_t>{ 0, 0, 0, 0 }), positions[65].rect);
+    // 'A' was not placed because not in the glyph set.
+    ASSERT_EQ(positions.end(), positions.find(65));
 
     // 'B' was placed at the top left.
     ASSERT_NE(positions.end(), positions.find(66));
diff --git a/test/text/glyph_pbf.test.cpp b/test/text/glyph_pbf.test.cpp
index 1e28dfbc31..be3ca3359b 100644
--- a/test/text/glyph_pbf.test.cpp
+++ b/test/text/glyph_pbf.test.cpp
@@ -44,15 +44,17 @@ TEST(GlyphPBF, Parsing) {
     glyphAtlasObserver.glyphsLoaded = [&](const FontStack&, const GlyphRange&) {
         loop.stop();
 
-        auto sdfs = glyphAtlas.getGlyphSet(fontStack)->getSDFs();
+        const auto& sdfs = glyphAtlas.getGlyphSet(fontStack)->getSDFs();
 
         // The fake glyphs don't contain a glyph that has the ID 0; it only contains glyphs with
         // undefined IDs, but the parser should remove them.
 
         EXPECT_TRUE(sdfs.size() == 1);
         EXPECT_TRUE(sdfs.find(69) != sdfs.end());
-        auto& sdf = sdfs[69];
-        EXPECT_EQ("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"s, sdf.bitmap);
+        auto& sdf = sdfs.at(69);
+        AlphaImage expected({7, 7});
+        expected.fill('x');
+        EXPECT_EQ(expected, sdf.bitmap);
         EXPECT_EQ(1u, sdf.metrics.width);
         EXPECT_EQ(1u, sdf.metrics.height);
         EXPECT_EQ(20, sdf.metrics.left);