renderer/text_renderer_directwrite: Implement halfwidth glyph substit…

…ution
xqq · Sep 17, 2023 · 8c01527 · 8c01527
1 parent a05ae6a
commit 8c01527
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Showing 4 changed files with 36 additions and 2 deletions.
diff --git a/include/aribcaption/renderer.h b/include/aribcaption/renderer.h
@@ -317,7 +317,8 @@ ARIBCC_API bool aribcc_renderer_set_language_specific_font_family(aribcc_rendere
  * If the font has Std, Pr5, Pr6, Pr7, or Pro in the name, it is likely to be compliant.
  * Fonts such as IBM Plex Sans JP, Morisawa BIZ UDGothic, Morisawa BIZ UDMincho,
  * Yu Gothic, Yu Mincho, and Meiryo are also supported.
- * It is enabled by default when using the FreeType renderer, but has no effect when using other renderers.
+ * It is only effective when using the FreeType or DirectWrite renderer,
+ * and is enabled by default for these renderers.
  *
  * @param decoder @aribcc_decoder_t
  * @param replace If true is specified, Captions that use halfwidth kana, halfwidth symbol and

diff --git a/include/aribcaption/renderer.hpp b/include/aribcaption/renderer.hpp
@@ -252,7 +252,8 @@ class Renderer {
      * If the font has Std, Pr5, Pr6, Pr7, or Pro in the name, it is likely to be compliant.
      * Fonts such as IBM Plex Sans JP, Morisawa BIZ UDGothic, Morisawa BIZ UDMincho,
      * Yu Gothic, Yu Mincho, and Meiryo are also supported.
-     * It is enabled by default when using the FreeType renderer, but has no effect when using other renderers.
+     * It is only effective when using the FreeType or DirectWrite renderer,
+     * and is enabled by default for these renderers.
      *
      * @param replace If true is specified, Captions that use halfwidth kana, halfwidth symbol and
      *                halfwidth alphanumeric characters will look better.

diff --git a/src/renderer/text_renderer_directwrite.cpp b/src/renderer/text_renderer_directwrite.cpp
@@ -275,6 +275,10 @@ bool TextRendererDirectWrite::SetFontFamily(const std::vector<std::string>& font
     return false;
 }
 
+void TextRendererDirectWrite::SetReplaceMSZHalfWidthGlyph(bool replace) {
+    replace_msz_halfwidth_glyph_ = replace;
+}
+
 struct TextRenderContextPrivateDirectWrite : public TextRenderContext::ContextPrivate {
 public:
     TextRenderContextPrivateDirectWrite() = default;
@@ -467,6 +471,31 @@ auto TextRendererDirectWrite::DrawChar(TextRenderContext& render_ctx, int target
         return TextRenderStatus::kOtherError;
     }
 
+    // Check if the font has a half width glyph for this character.
+    if (replace_msz_halfwidth_glyph_ && is_requesting_halfwidth) {
+        ComPtr<IDWriteTypography> typography;
+        DWRITE_TEXT_METRICS full_width_text_metrics = metrics;
+        DWRITE_FONT_FEATURE feature = {DWRITE_FONT_FEATURE_TAG_HALF_WIDTH, 1};
+        if (SUCCEEDED(dwrite_factory_->CreateTypography(&typography)) &&
+            SUCCEEDED(typography->AddFontFeature(feature)) &&
+            SUCCEEDED(text_layout->SetTypography(typography.Get(), DWRITE_TEXT_RANGE{0, 1}))) {
+            hr = text_layout->GetMetrics(&metrics);
+            if (FAILED(hr)) {
+                log_->e("TextRendererDirectWrite: GetMetrics() failed");
+                return TextRenderStatus::kOtherError;
+            }
+            // Avoid scaling because it has a half width glyph.
+            if (full_width_text_metrics.width / 2 == metrics.width) {
+                char_width = char_height;
+                horizontal_scale = 1.0f;
+            } else {
+                if (SUCCEEDED(dwrite_factory_->CreateTypography(&typography))) {
+                    text_layout->SetTypography(typography.Get(), DWRITE_TEXT_RANGE{0, 1});
+                }
+            }
+        }
+    }
+
     // Calculate charbox size
     int charbox_width = static_cast<int>(ceilf((metrics.width + (float)margin_x * 2) * horizontal_scale));
     int charbox_height = static_cast<int>(ceilf(metrics.height)) + margin_y * 2;

diff --git a/src/renderer/text_renderer_directwrite.hpp b/src/renderer/text_renderer_directwrite.hpp
@@ -41,6 +41,7 @@ class TextRendererDirectWrite : public TextRenderer {
     bool Initialize() override;
     void SetLanguage(uint32_t iso6392_language_code) override;
     bool SetFontFamily(const std::vector<std::string>& font_family) override;
+    void SetReplaceMSZHalfWidthGlyph(bool replace) override;
     auto BeginDraw(Bitmap& target_bmp) -> TextRenderContext override;
     void EndDraw(TextRenderContext& context) override;
     auto DrawChar(TextRenderContext& render_ctx, int x, int y,
@@ -82,6 +83,8 @@ class TextRendererDirectWrite : public TextRenderer {
 
     ComPtr<IDWriteTextFormat> main_text_format_;
     ComPtr<IDWriteTextFormat> fallback_text_format_;
+
+    bool replace_msz_halfwidth_glyph_ = true;
 };
 
 }  // namespace aribcaption