Merge branch 'round-glyphs-option' into 'master'

Round glyphs option

See merge request GNOME/pango!120

11 files changed, 185 insertions, 37 deletions

diff --git a/.gitlab-ci/render-msys2.sh b/.gitlab-ci/render-msys2.sh
index f81f0c60..8d13e9bc 100644
--- a/.gitlab-ci/render-msys2.sh
+++ b/.gitlab-ci/render-msys2.sh
@@ -2,4 +2,4 @@
 
 set -e
 
-PATH=_build/pango:$PATH _build/utils/pango-view --no-display --output _build/hello.png utils/HELLO.txt
+PATH=_build/pango:$PATH gdb --eval-command=run --args _build/utils/pango-view --no-display --output _build/hello.png utils/HELLO.txt
diff --git a/docs/pango-sections.txt b/docs/pango-sections.txt
index 78a6b4cb..7a95d401 100644
--- a/docs/pango-sections.txt
+++ b/docs/pango-sections.txt
@@ -30,6 +30,8 @@ PangoLogAttr
 <SUBSECTION>
 pango_shape
 pango_shape_full
+PangoShapeFlags
+pango_shape_with_flags
 
 <SUBSECTION Standard>
 PANGO_TYPE_ITEM
@@ -60,6 +62,8 @@ pango_context_get_gravity_hint
 pango_context_set_gravity_hint
 pango_context_get_matrix
 pango_context_set_matrix
+pango_context_get_round_glyph_positions
+pango_context_set_round_glyph_positions
 pango_context_load_font
 pango_context_load_fontset
 pango_context_get_metrics
diff --git a/pango/pango-context.c b/pango/pango-context.c
index 6ba64ce1..99fa454a 100644
--- a/pango/pango-context.c
+++ b/pango/pango-context.c
@@ -79,6 +79,8 @@ struct _PangoContext
   PangoMatrix *matrix;
 
   PangoFontMap *font_map;
+
+  gboolean round_glyph_positions;
 };
 
 struct _PangoContextClass
@@ -103,6 +105,7 @@ pango_context_init (PangoContext *context)
   context->set_language = NULL;
   context->language = pango_language_get_default ();
   context->font_map = NULL;
+  context->round_glyph_positions = TRUE;
 
   context->font_desc = pango_font_description_new ();
   pango_font_description_set_family_static (context->font_desc, "serif");
@@ -1857,3 +1860,46 @@ pango_context_get_serial (PangoContext *context)
   check_fontmap_changed (context);
   return context->serial;
 }
+
+/**
+ * pango_context_set_round_glyph_positions:
+ * @context: a #PangoContext
+ * @round_positions: whether to round glyph positions
+ *
+ * Sets whether font rendering with this context should
+ * round glyph positions and widths to integral positions,
+ * in device units.
+ *
+ * This is useful when the renderer can't handle subpixel
+ * positioning of glyphs.
+ *
+ * The default value is to round glyph positions, to remain
+ * compatible with previous Pango behavior.
+ *
+ * Since: 1.44
+ */
+void
+pango_context_set_round_glyph_positions (PangoContext *context,
+                                         gboolean      round_positions)
+{
+  if (context->round_glyph_positions != round_positions)
+    {
+      context->round_glyph_positions = round_positions;
+      context_changed (context);
+    }
+}
+
+/**
+ * pango_context_get_round_glyph_positions:
+ * @context: a #PangoContext
+ *
+ * Returns whether font rendering with this context should
+ * round glyph positions and widths.
+ *
+ * Since: 1.44
+ */
+gboolean
+pango_context_get_round_glyph_positions (PangoContext *context)
+{
+  return context->round_glyph_positions;
+}
diff --git a/pango/pango-context.h b/pango/pango-context.h
index af934491..0f775ff4 100644
--- a/pango/pango-context.h
+++ b/pango/pango-context.h
@@ -113,6 +113,13 @@ void                      pango_context_set_matrix           (PangoContext
 PANGO_AVAILABLE_IN_1_6
 const PangoMatrix *       pango_context_get_matrix           (PangoContext      *context);
 
+PANGO_AVAILABLE_IN_1_44
+void                      pango_context_set_round_glyph_positions (PangoContext *context,
+                                                                   gboolean      round_positions);
+PANGO_AVAILABLE_IN_1_44
+gboolean                  pango_context_get_round_glyph_positions (PangoContext *context);
+
+
 /* Break a string of Unicode characters into segments with
  * consistent shaping/language engine and bidrectional level.
  * Returns a #GList of #PangoItem's
diff --git a/pango/pango-glyph.h b/pango/pango-glyph.h
index 917ec570..628eac96 100644
--- a/pango/pango-glyph.h
+++ b/pango/pango-glyph.h
@@ -189,18 +189,43 @@ void pango_glyph_string_x_to_index (PangoGlyphString *glyphs,
 /* Turn a string of characters into a string of glyphs
  */
 PANGO_AVAILABLE_IN_ALL
-void pango_shape (const gchar      *text,
-		  gint              length,
-		  const PangoAnalysis *analysis,
-		  PangoGlyphString *glyphs);
+void pango_shape (const char          *text,
+                  int                  length,
+                  const PangoAnalysis *analysis,
+                  PangoGlyphString    *glyphs);
 
 PANGO_AVAILABLE_IN_1_32
-void pango_shape_full (const gchar      *item_text,
-		       gint              item_length,
-		       const gchar      *paragraph_text,
-		       gint              paragraph_length,
-		       const PangoAnalysis *analysis,
-		       PangoGlyphString *glyphs);
+void pango_shape_full (const char          *item_text,
+                       int                  item_length,
+                       const char          *paragraph_text,
+                       int                  paragraph_length,
+                       const PangoAnalysis *analysis,
+                       PangoGlyphString    *glyphs);
+
+/**
+ * PangoShapeFlags:
+ * @PANGO_SHAPE_NONE: Default value.
+ * @PANGO_SHAPE_ROUND_POSITIONS: Round glyph positions
+ *     and widths to whole device units. This option should
+ *     be set if the target renderer can't do subpixel
+ *     positioning of glyphs.
+ *
+ * Flags influencing the shaping process.
+ * These can be passed to pango_shape_with_flags().
+ */
+typedef enum {
+  PANGO_SHAPE_NONE            = 0,
+  PANGO_SHAPE_ROUND_POSITIONS = 1 << 0,
+} PangoShapeFlags;
+
+PANGO_AVAILABLE_IN_1_44
+void pango_shape_with_flags (const char          *item_text,
+                             int                  item_length,
+                             const char          *paragraph_text,
+                             int                  paragraph_length,
+                             const PangoAnalysis *analysis,
+                             PangoGlyphString    *glyphs,
+                             PangoShapeFlags      flags);
 
 PANGO_AVAILABLE_IN_ALL
 GList *pango_reorder_items (GList *logical_items);
diff --git a/pango/pango-layout.c b/pango/pango-layout.c
index 521f806a..0ddb6e14 100644
--- a/pango/pango-layout.c
+++ b/pango/pango-layout.c
@@ -3354,14 +3354,20 @@ shape_run (PangoLayoutLine *line,
     shape_tab (line, item, glyphs);
   else
     {
+      PangoShapeFlags shape_flags = PANGO_SHAPE_NONE;
+
+      if (pango_context_get_round_glyph_positions (layout->context))
+        shape_flags |= PANGO_SHAPE_ROUND_POSITIONS;
+
       if (state->properties.shape_set)
 	_pango_shape_shape (layout->text + item->offset, item->num_chars,
 			    state->properties.shape_ink_rect, state->properties.shape_logical_rect,
 			    glyphs);
       else
-        pango_shape_full (layout->text + item->offset, item->length,
-                          layout->text, layout->length,
-                          &item->analysis, glyphs);
+        pango_shape_with_flags (layout->text + item->offset, item->length,
+                                layout->text, layout->length,
+                                &item->analysis, glyphs,
+                                shape_flags);
 
       if (state->properties.letter_spacing)
 	{
diff --git a/pango/shape.c b/pango/shape.c
index cb969e67..efdb3177 100644
--- a/pango/shape.c
+++ b/pango/shape.c
@@ -55,14 +55,51 @@
  * boundaries.
  */
 void
-pango_shape (const gchar      *text,
-	     gint              length,
+pango_shape (const gchar         *text,
+	     gint                 length,
 	     const PangoAnalysis *analysis,
-	     PangoGlyphString *glyphs)
+	     PangoGlyphString    *glyphs)
 {
   pango_shape_full (text, length, text, length, analysis, glyphs);
 }
 
+/**
+ * pango_shape_full:
+ * @item_text:        valid UTF-8 text to shape.
+ * @item_length:      the length (in bytes) of @item_text. -1 means nul-terminated text.
+ * @paragraph_text: (allow-none): text of the paragraph (see details).  May be %NULL.
+ * @paragraph_length: the length (in bytes) of @paragraph_text. -1 means nul-terminated text.
+ * @analysis:  #PangoAnalysis structure from pango_itemize().
+ * @glyphs:    glyph string in which to store results.
+ *
+ * Given a segment of text and the corresponding
+ * #PangoAnalysis structure returned from pango_itemize(),
+ * convert the characters into glyphs. You may also pass
+ * in only a substring of the item from pango_itemize().
+ *
+ * This is similar to pango_shape(), except it also can optionally take
+ * the full paragraph text as input, which will then be used to perform
+ * certain cross-item shaping interactions.  If you have access to the broader
+ * text of which @item_text is part of, provide the broader text as
+ * @paragraph_text.  If @paragraph_text is %NULL, item text is used instead.
+ *
+ * Since: 1.32
+ */
+void
+pango_shape_full (const char          *item_text,
+                  int                  item_length,
+                  const char          *paragraph_text,
+                  int                  paragraph_length,
+                  const PangoAnalysis *analysis,
+                  PangoGlyphString    *glyphs)
+{
+  pango_shape_with_flags (item_text, item_length,
+                          paragraph_text, paragraph_length,
+                          analysis,
+                          glyphs,
+                          PANGO_SHAPE_NONE);
+}
+
 static void
 fallback_shape (const char          *text,
                 unsigned int         length,
@@ -113,34 +150,36 @@ fallback_shape (const char          *text,
 }
 
 /**
- * pango_shape_full:
- * @item_text:        valid UTF-8 text to shape.
- * @item_length:      the length (in bytes) of @item_text. -1 means nul-terminated text.
- * @paragraph_text: (allow-none): text of the paragraph (see details).  May be %NULL.
- * @paragraph_length: the length (in bytes) of @paragraph_text. -1 means nul-terminated text.
- * @analysis:  #PangoAnalysis structure from pango_itemize().
- * @glyphs:    glyph string in which to store results.
+ * pango_shape_with_flags:
+ * @item_text: valid UTF-8 text to shape
+ * @item_length: the length (in bytes) of @item_text.
+ *     -1 means nul-terminated text.
+ * @paragraph_text: (allow-none): text of the paragraph (see details).
+ *     May be %NULL.
+ * @paragraph_length: the length (in bytes) of @paragraph_text.
+ *     -1 means nul-terminated text.
+ * @analysis:  #PangoAnalysis structure from pango_itemize()
+ * @glyphs: glyph string in which to store results
+ * @flags: flags influencing the shaping process
  *
  * Given a segment of text and the corresponding
  * #PangoAnalysis structure returned from pango_itemize(),
  * convert the characters into glyphs. You may also pass
  * in only a substring of the item from pango_itemize().
  *
- * This is similar to pango_shape(), except it also can optionally take
- * the full paragraph text as input, which will then be used to perform
- * certain cross-item shaping interactions.  If you have access to the broader
- * text of which @item_text is part of, provide the broader text as
- * @paragraph_text.  If @paragraph_text is %NULL, item text is used instead.
+ * This is similar to pango_shape_full(), except it also takes
+ * flags that can influence the shaping process.
  *
- * Since: 1.32
+ * Since: 1.44
  */
 void
-pango_shape_full (const gchar      *item_text,
-		  gint              item_length,
-		  const gchar      *paragraph_text,
-		  gint              paragraph_length,
-		  const PangoAnalysis *analysis,
-		  PangoGlyphString *glyphs)
+pango_shape_with_flags (const gchar         *item_text,
+                        gint                 item_length,
+                        const gchar         *paragraph_text,
+                        gint                 paragraph_length,
+                        const PangoAnalysis *analysis,
+                        PangoGlyphString    *glyphs,
+                        PangoShapeFlags      flags)
 {
   int i;
   int last_cluster;
@@ -243,4 +282,14 @@ pango_shape_full (const gchar      *item_text,
       /* *Fix* it so we don't crash later */
       pango_glyph_string_reverse_range (glyphs, 0, glyphs->num_glyphs);
     }
+
+  if (flags & PANGO_SHAPE_ROUND_POSITIONS)
+    {
+      for (i = 0; i < glyphs->num_glyphs; i++)
+        {
+          glyphs->glyphs[i].geometry.width    = PANGO_UNITS_ROUND (glyphs->glyphs[i].geometry.width );
+          glyphs->glyphs[i].geometry.x_offset = PANGO_UNITS_ROUND (glyphs->glyphs[i].geometry.x_offset);
+          glyphs->glyphs[i].geometry.y_offset = PANGO_UNITS_ROUND (glyphs->glyphs[i].geometry.y_offset);
+        }
+    }
 }
diff --git a/tests/test-harfbuzz.c b/tests/test-harfbuzz.c
index f9392b67..cba9026c 100644
--- a/tests/test-harfbuzz.c
+++ b/tests/test-harfbuzz.c
@@ -37,7 +37,10 @@ test_hb_font (void)
   hb_bool_t res;
   hb_codepoint_t glyph;
 
-  desc = pango_font_description_from_string ("Cantarell 11");
+ if (strcmp (G_OBJECT_TYPE_NAME (pango_context_get_font_map (context)), "PangoCairoWin32FontMap") == 0)
+    desc = pango_font_description_from_string ("Verdana 11");
+  else
+    desc = pango_font_description_from_string ("Cantarell 11");
   font = pango_context_load_font (context, desc);
   hb_font = pango_font_get_hb_font (font);
 
diff --git a/utils/viewer-pangocairo.c b/utils/viewer-pangocairo.c
index f82bd72d..ac3b49c3 100644
--- a/utils/viewer-pangocairo.c
+++ b/utils/viewer-pangocairo.c
@@ -36,6 +36,7 @@ typedef struct
 
   PangoFontMap *fontmap;
   cairo_font_options_t *font_options;
+  gboolean subpixel_positions;
 } CairoViewer;
 
 static gpointer
@@ -73,6 +74,8 @@ pangocairo_view_create (const PangoViewer *klass G_GNUC_UNUSED)
   if (opt_antialias != ANTIALIAS_DEFAULT)
     cairo_font_options_set_antialias (instance->font_options, (cairo_antialias_t)opt_antialias);
 
+  instance->subpixel_positions = opt_subpixel_positions;
+
   return instance;
 }
 
@@ -100,6 +103,7 @@ pangocairo_view_get_context (gpointer instance)
 
   context = pango_font_map_create_context (c->fontmap);
   pango_cairo_context_set_font_options (context, c->font_options);
+  pango_context_set_round_glyph_positions (context, !c->subpixel_positions);
 
   return context;
 }
diff --git a/utils/viewer-render.c b/utils/viewer-render.c
index 36cee596..82b30f05 100644
--- a/utils/viewer-render.c
+++ b/utils/viewer-render.c
@@ -63,6 +63,7 @@ HintMode opt_hinting = HINT_DEFAULT;
 HintMetrics opt_hint_metrics = HINT_METRICS_DEFAULT;
 SubpixelOrder opt_subpixel_order = SUBPIXEL_DEFAULT;
 Antialias opt_antialias = ANTIALIAS_DEFAULT;
+gboolean opt_subpixel_positions = FALSE;
 PangoWrapMode opt_wrap = PANGO_WRAP_WORD_CHAR;
 gboolean opt_wrap_set = FALSE;
 static const char *opt_pangorc = NULL; /* Unused */
@@ -800,6 +801,8 @@ parse_options (int argc, char *argv[])
      "Antialiasing",                                        "none/gray/subpixel"},
     {"hint-metrics",    0, 0, G_OPTION_ARG_CALLBACK,                    &parse_hint_metrics,
      "Hint metrics",                                        "on/off"},
+    { "subpixel-positions", 0, 0, G_OPTION_ARG_NONE,                    &opt_subpixel_positions,
+     "Subpixel positioning",                                        NULL},
     {"subpixel-order",  0, 0, G_OPTION_ARG_CALLBACK,                    &parse_subpixel_order,
      "Subpixel order",                                      "rgb/bgr/vrgb/vbgr"},
     {"indent",		0, 0, G_OPTION_ARG_INT,				&opt_indent,
diff --git a/utils/viewer-render.h b/utils/viewer-render.h
index bfb50e55..3ffc42e4 100644
--- a/utils/viewer-render.h
+++ b/utils/viewer-render.h
@@ -107,6 +107,7 @@ extern HintMode opt_hinting;
 extern SubpixelOrder opt_subpixel_order;
 extern Antialias opt_antialias;
 extern HintMetrics opt_hint_metrics;
+extern gboolean opt_subpixel_positions;
 extern PangoColor opt_fg_color;
 extern guint16 opt_fg_alpha;
 extern gboolean opt_bg_set;