Text: taking a pointer in cache.findFont() is stupid, don't.

Especially given that nullptr causes an assert. All call sites basically
ended up passing a &font and all that extra annoyance just doesn't make
sense.

Given this API is still relatively recent, I'm not bothering with
backwards compatibility.

doc/snippets/MagnumText.cpp

@@ -237,7 +237,7 @@ Text::AbstractGlyphCache& cache = DOXYGEN_ELLIPSIS(cacheInstance);
 
 Containers::ArrayView<const UnsignedInt> fontGlyphIds = DOXYGEN_ELLIPSIS({});
 
-Containers::Optional<UnsignedInt> fontId = cache.findFont(font.get());
+Containers::Optional<UnsignedInt> fontId = cache.findFont(*font);
 DOXYGEN_ELLIPSIS()
 for(std::size_t i = 0; i != fontGlyphIds.size(); ++i) {
     Containers::Triple<Vector2i, Int, Range2Di> glyph =

src/Magnum/Text/AbstractFont.cpp

@@ -324,7 +324,7 @@ Containers::Pointer<AbstractLayouter> AbstractFont::layout(const AbstractGlyphCa
         "Text::AbstractFont::layout(): array glyph caches are not supported", {});
 
     /* Find this font in the cache. This is kept as a runtime error however. */
-    Containers::Optional<UnsignedInt> fontId = cache.findFont(this);
+    Containers::Optional<UnsignedInt> fontId = cache.findFont(*this);
     if(!fontId) {
         Error{} << "Text::AbstractFont::layout(): font not found among" << cache.fontCount() << "fonts in passed glyph cache";
         return {};

src/Magnum/Text/AbstractGlyphCache.cpp

@@ -246,12 +246,10 @@ const AbstractFont* AbstractGlyphCache::fontPointer(const UnsignedInt fontId) co
     return state.fonts[fontId].pointer;
 }
 
-Containers::Optional<UnsignedInt> AbstractGlyphCache::findFont(const AbstractFont* pointer) const {
-    CORRADE_ASSERT(pointer,
-        "Text::AbstractGlyphCache::findFont(): expected a non-null pointer", {});
+Containers::Optional<UnsignedInt> AbstractGlyphCache::findFont(const AbstractFont& font) const {
     const State& state = *_state;
     for(UnsignedInt i = 0; i != state.fonts.size() - 1; ++i)
-        if(state.fonts[i].pointer == pointer) return i;
+        if(state.fonts[i].pointer == &font) return i;
     return {};
 }
 

src/Magnum/Text/AbstractGlyphCache.h

@@ -457,9 +457,9 @@ class MAGNUM_TEXT_EXPORT AbstractGlyphCache {
          * @brief Add a font
          * @param glyphCount    Upper bound on glyph IDs present in the font,
          *      or the value of @ref AbstractFont::glyphCount()
-         * @param pointer       Optional unique font identifier for later
-         *      lookup via @ref findFont(). Use @cpp nullptr @ce if not
-         *      associated with any particular font instance.
+         * @param pointer       Font instance for later lookup via
+         *      @ref findFont(). Use @cpp nullptr @ce if not associated with
+         *      any particular font instance.
          * @m_since_latest
          *
          * Returns font ID that's subsequently used to identify the font in
@@ -491,16 +491,15 @@ class MAGNUM_TEXT_EXPORT AbstractGlyphCache {
         const AbstractFont* fontPointer(UnsignedInt fontId) const;
 
         /**
-         * @brief Find a font ID for a unique font identifier
+         * @brief Find a font ID for a font instance
          * @m_since_latest
          *
-         * The @p pointer is expected to not be @cpp nullptr @ce, as there can
-         * be multiple fonts with no associated identifier. If no font is found
-         * for given identifier, returns @ref Containers::NullOpt. The lookup
-         * is done with an @f$ \mathcal{O}(n) @f$ complexity with @f$ n @f$
-         * being @ref fontCount().
+         * Returns a font ID if a pointer matching @p font was used in an
+         * earlier @ref addFont() call, @ref Containers::NullOpt otherwise. The
+         * lookup is done with an @f$ \mathcal{O}(n) @f$ complexity with
+         * @f$ n @f$ being @ref fontCount().
          */
-        Containers::Optional<UnsignedInt> findFont(const AbstractFont* pointer) const;
+        Containers::Optional<UnsignedInt> findFont(const AbstractFont& font) const;
 
         #ifdef MAGNUM_BUILD_DEPRECATED
         /**

src/Magnum/Text/Renderer.cpp

@@ -140,7 +140,7 @@ Range2D renderGlyphQuadsInto(const AbstractFont& font, const Float size, const A
     CORRADE_ASSERT(font.isOpened(),
         "Text::renderGlyphQuadsInto(): no font opened", {});
 
-    const Containers::Optional<UnsignedInt> fontId = cache.findFont(&font);
+    const Containers::Optional<UnsignedInt> fontId = cache.findFont(font);
     CORRADE_ASSERT(fontId,
         "Text::renderGlyphQuadsInto(): font not found among" << cache.fontCount() << "fonts in passed glyph cache", {});
 
@@ -303,7 +303,7 @@ std::tuple<std::vector<Vertex>, Range2D> renderVerticesInternal(AbstractFont& fo
 
     /* Find this font in the cache and assert in the high-level API already to
        avoid confusion */
-    CORRADE_ASSERT(cache.findFont(&font),
+    CORRADE_ASSERT(cache.findFont(font),
         "Text::Renderer: font not found among" << cache.fontCount() << "fonts in passed glyph cache", {});
 
     /* Output data, reserve memory as when the text would be ASCII-only. In

src/Magnum/Text/Test/AbstractGlyphCacheTest.cpp

@@ -85,7 +85,6 @@ struct AbstractGlyphCacheTest: TestSuite::Tester {
     void addFont();
     void addFontDuplicatePointer();
     void fontOutOfRange();
-    void findFontNullptr();
 
     #ifdef MAGNUM_BUILD_DEPRECATED
     void reserve();
@@ -182,7 +181,6 @@ AbstractGlyphCacheTest::AbstractGlyphCacheTest() {
               &AbstractGlyphCacheTest::addFont,
               &AbstractGlyphCacheTest::addFontDuplicatePointer,
               &AbstractGlyphCacheTest::fontOutOfRange,
-              &AbstractGlyphCacheTest::findFontNullptr,
 
               #ifdef MAGNUM_BUILD_DEPRECATED
               &AbstractGlyphCacheTest::reserve,
@@ -603,21 +601,21 @@ void AbstractGlyphCacheTest::addFont() {
     DummyGlyphCache cache{PixelFormat::R32F, {1024, 512}};
 
     const AbstractFont* font = reinterpret_cast<const AbstractFont*>(0xdeadbeef);
-    CORRADE_COMPARE(cache.findFont(font), Containers::NullOpt);
+    CORRADE_COMPARE(cache.findFont(*font), Containers::NullOpt);
 
     CORRADE_COMPARE(cache.addFont(35, nullptr), 0);
     CORRADE_COMPARE(cache.fontCount(), 1);
     CORRADE_COMPARE(cache.glyphCount(), 1);
     CORRADE_COMPARE(cache.fontGlyphCount(0), 35);
     CORRADE_COMPARE(cache.fontPointer(0), nullptr);
-    CORRADE_COMPARE(cache.findFont(font), Containers::NullOpt);
+    CORRADE_COMPARE(cache.findFont(*font), Containers::NullOpt);
 
     CORRADE_COMPARE(cache.addFont(12, font), 1);
     CORRADE_COMPARE(cache.fontCount(), 2);
     CORRADE_COMPARE(cache.glyphCount(), 1);
     CORRADE_COMPARE(cache.fontGlyphCount(1), 12);
     CORRADE_COMPARE(cache.fontPointer(1), font);
-    CORRADE_COMPARE(cache.findFont(font), 1);
+    CORRADE_COMPARE(cache.findFont(*font), 1);
 }
 
 void AbstractGlyphCacheTest::addFontDuplicatePointer() {
@@ -653,17 +651,6 @@ void AbstractGlyphCacheTest::fontOutOfRange() {
         "Text::AbstractGlyphCache::fontPointer(): index 2 out of range for 2 fonts\n");
 }
 
-void AbstractGlyphCacheTest::findFontNullptr() {
-    CORRADE_SKIP_IF_NO_ASSERT();
-
-    DummyGlyphCache cache{PixelFormat::R32F, {1024, 512}};
-
-    std::ostringstream out;
-    Error redirectError{&out};
-    cache.findFont(nullptr);
-    CORRADE_COMPARE(out.str(), "Text::AbstractGlyphCache::findFont(): expected a non-null pointer\n");
-}
-
 #ifdef MAGNUM_BUILD_DEPRECATED
 void AbstractGlyphCacheTest::reserve() {
     DummyGlyphCache cache{PixelFormat::R8Unorm, {24, 20}, {1, 2}};

src/MagnumPlugins/MagnumFont/Test/MagnumFontGLTest.cpp

@@ -88,7 +88,7 @@ void MagnumFontGLTest::createGlyphCache() {
 
     /* The font should associate itself with the cache */
     CORRADE_COMPARE(cache->fontCount(), 1);
-    CORRADE_COMPARE(cache->findFont(font.get()), 0);
+    CORRADE_COMPARE(cache->findFont(*font), 0);
 
     /* Verify glyph contents */
     CORRADE_COMPARE(cache->glyphCount(), 5);
@@ -162,7 +162,7 @@ void MagnumFontGLTest::createGlyphCacheProcessedImage() {
 
     /* The font should associate itself with the cache */
     CORRADE_COMPARE(cache->fontCount(), 1);
-    CORRADE_COMPARE(cache->findFont(font.get()), 0);
+    CORRADE_COMPARE(cache->findFont(*font), 0);
 
     /* Verify glyph contents */
     CORRADE_COMPARE(cache->glyphCount(), 5);
@@ -233,7 +233,7 @@ void MagnumFontGLTest::createGlyphCacheNoGlyphs() {
 
     /* The font should associate itself with the cache even in this case */
     CORRADE_COMPARE(cache->fontCount(), 1);
-    CORRADE_COMPARE(cache->findFont(font.get()), 0);
+    CORRADE_COMPARE(cache->findFont(*font), 0);
 
     /* There's just the empty glyph added by the cache itself, nothing else */
     CORRADE_COMPARE(cache->glyphCount(), 1);

src/MagnumPlugins/MagnumFontConverter/MagnumFontConverter.cpp

@@ -63,7 +63,7 @@ std::vector<std::pair<std::string, Containers::Array<char>>> MagnumFontConverter
         return {};
     }
 
-    Containers::Optional<UnsignedInt> fontId = cache.findFont(&font);
+    Containers::Optional<UnsignedInt> fontId = cache.findFont(font);
     #ifdef MAGNUM_BUILD_DEPRECATED
     /* Make it work with the old-style glyph cache filling that adds exactly
        one font into the cache and doesn't associate any pointer with it */