Text: implicitly add "Not Found" glyph to GlyphCache.

Also added test for GlyphCache functionality.

src/Text/GlyphCache.cpp

@@ -55,12 +55,15 @@ GlyphCache::GlyphCache(const Vector2i& size, const Vector2i& padding): _size(siz
 
 GlyphCache::~GlyphCache() = default;
 
-/** @todo Delegating constructor when support for GCC 4.6 is dropped */
 void GlyphCache::initialize(const TextureFormat internalFormat, const Vector2i& size) {
+    /* Initialize texture */
     _texture.setWrapping(Sampler::Wrapping::ClampToEdge)
         ->setMinificationFilter(Sampler::Filter::Linear)
         ->setMagnificationFilter(Sampler::Filter::Linear)
         ->setStorage(1, internalFormat, size);
+
+    /* Default "Not Found" glyph */
+    glyphs.insert({0, {}});
 }
 
 std::vector<Rectanglei> GlyphCache::reserve(const std::vector<Vector2i>& sizes) {
@@ -74,7 +77,11 @@ void GlyphCache::insert(const UnsignedInt glyph, Vector2i position, Rectanglei r
     rectangle.bottomLeft() -= _padding;
     rectangle.topRight() += _padding;
 
-    glyphs.insert({glyph, {position, rectangle}});
+    /* Overwriting "Not Found" glyph */
+    if(glyph == 0) glyphs[0] = {position, rectangle};
+
+    /* Inserting new glyph */
+    else CORRADE_INTERNAL_ASSERT_OUTPUT(glyphs.insert({glyph, {position, rectangle}}).second);
 }
 
 void GlyphCache::setImage(const Vector2i& offset, const ImageReference2D& image) {

src/Text/GlyphCache.h

@@ -97,8 +97,11 @@ class MAGNUM_TEXT_EXPORT GlyphCache {
          * @param glyph         Glyph ID
          *
          * First tuple element is glyph position relative to point on baseline,
-         * second element is glyph region in texture atlas. If no glyph is
+         * second element is glyph region in texture atlas.
-         * found, glyph on zero index is returned.
+         *
+         * If no glyph is found, glyph `0` is returned, which is by default on
+         * zero position and has zero region in texture atlas. You can reset it
+         * to some meaningful value in insert().
          */
         std::pair<Vector2i, Rectanglei> operator[](UnsignedInt glyph) const {
             auto it = glyphs.find(glyph);
@@ -134,8 +137,11 @@ class MAGNUM_TEXT_EXPORT GlyphCache {
          * @param position      Position relative to point on baseline
          * @param rectangle     Region in texture atlas
          *
-         * You can obtain unused non-overlapping regions with reserve(). See
+         * You can obtain unused non-overlapping regions with reserve(). You
-         * also setImage() to upload glyph image.
+         * can't overwrite already inserted glyph, however you can reset glyph
+         * `0` to some meaningful value.
+         *
+         * See also setImage() to upload glyph image.
          */
         void insert(UnsignedInt glyph, Vector2i position, Rectanglei rectangle);
 

src/Text/Test/CMakeLists.txt

@@ -29,3 +29,7 @@ include_directories(${CMAKE_CURRENT_BINARY_DIR})
 
 corrade_add_test(TextAbstractFontTest AbstractFontTest.cpp LIBRARIES Magnum MagnumText)
 corrade_add_test(TextAbstractFontConverterTest AbstractFontConverterTest.cpp LIBRARIES Magnum MagnumText)
+
+if(BUILD_GL_TESTS)
+    corrade_add_test(TextGlyphCacheGLTest GlyphCacheGLTest.cpp LIBRARIES MagnumText ${GL_TEST_LIBRARIES})
+endif()

src/Text/Test/GlyphCacheGLTest.cpp

@@ -0,0 +1,83 @@
+/*
+    This file is part of Magnum.
+
+    Copyright © 2010, 2011, 2012, 2013 Vladimír Vondruš <mosra@centrum.cz>
+
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
+*/
+
+#include "Test/AbstractOpenGLTester.h"
+#include "Text/GlyphCache.h"
+
+namespace Magnum { namespace Text { namespace Test {
+
+class GlyphCacheGLTest: public Magnum::Test::AbstractOpenGLTester {
+    public:
+        explicit GlyphCacheGLTest();
+
+        void initialize();
+        void access();
+};
+
+GlyphCacheGLTest::GlyphCacheGLTest() {
+    addTests({&GlyphCacheGLTest::initialize,
+              &GlyphCacheGLTest::access});
+}
+
+void GlyphCacheGLTest::initialize() {
+    Text::GlyphCache cache({1024, 2048});
+    MAGNUM_VERIFY_NO_ERROR();
+
+    CORRADE_COMPARE(cache.texture()->imageSize(0), Vector2i(1024, 2048));
+}
+
+void GlyphCacheGLTest::access() {
+    Text::GlyphCache cache(Vector2i(236));
+    Vector2i position;
+    Rectanglei rectangle;
+
+    /* Default "Not Found" glyph */
+    CORRADE_COMPARE(cache.glyphCount(), 1);
+    std::tie(position, rectangle) = cache[0];
+    CORRADE_COMPARE(position, Vector2i(0, 0));
+    CORRADE_COMPARE(rectangle, Rectanglei({0, 0}, {0, 0}));
+
+    /* Overwrite "Not Found" glyph */
+    cache.insert(0, {3, 5}, {{10, 10}, {23, 45}});
+    CORRADE_COMPARE(cache.glyphCount(), 1);
+    std::tie(position, rectangle) = cache[0];
+    CORRADE_COMPARE(position, Vector2i(3, 5));
+    CORRADE_COMPARE(rectangle, Rectanglei({10, 10}, {23, 45}));
+
+    /* Querying available glyph */
+    cache.insert(25, {3, 4}, {{15, 30}, {45, 35}});
+    CORRADE_COMPARE(cache.glyphCount(), 2);
+    std::tie(position, rectangle) = cache[25];
+    CORRADE_COMPARE(position, Vector2i(3, 4));
+    CORRADE_COMPARE(rectangle, Rectanglei({15, 30}, {45, 35}));
+
+    /* Querying not available glyph falls back to "Not Found" */
+    std::tie(position, rectangle) = cache[42];
+    CORRADE_COMPARE(position, Vector2i(3, 5));
+    CORRADE_COMPARE(rectangle, Rectanglei({10, 10}, {23, 45}));
+}
+
+}}}
+
+CORRADE_TEST_MAIN(Magnum::Text::Test::GlyphCacheGLTest)