[gtk/small-text-fixes: 1/4] gsk: Add font options to text nodes

[Matthias Clasen <matthiasc src gnome org>]

commit f1347f5841ea526c7016a8fbd329b45001812a23
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Sep 3 07:15:52 2021 -0400

    gsk: Add font options to text nodes
    
    Since font options affect how the glyphs get rendered,
    we need to pass the font options down from the gtk level
    to where the glyph cache is populated.
    
    Add a new gsk_text_node_new_full api that takes a
    cairo_font_options_t in addition to the other parameters.

 gsk/gskrendernode.h     |  13 ++++
 gsk/gskrendernodeimpl.c | 159 ++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 152 insertions(+), 20 deletions(-)
---
diff --git a/gsk/gskrendernode.h b/gsk/gskrendernode.h
index c420633a91..c362ddb70c 100644
--- a/gsk/gskrendernode.h
+++ b/gsk/gskrendernode.h
@@ -492,6 +492,19 @@ GskRenderNode *         gsk_text_node_new                       (PangoFont
                                                                  PangoGlyphString         *glyphs,
                                                                  const GdkRGBA            *color,
                                                                  const graphene_point_t   *offset);
+GDK_AVAILABLE_IN_4_6
+GskRenderNode *         gsk_text_node_new_with_font_options     (const cairo_font_options_t *options,
+                                                                 PangoFont                  *font,
+                                                                 PangoGlyphString           *glyphs,
+                                                                 const GdkRGBA              *color,
+                                                                 const graphene_point_t     *offset);
+
+GDK_AVAILABLE_IN_4_6
+gboolean                gsk_text_node_get_hint_metrics          (const GskRenderNode      *node) G_GNUC_PURE;
+GDK_AVAILABLE_IN_4_6
+gboolean                gsk_text_node_get_antialias             (const GskRenderNode      *node) G_GNUC_PURE;
+GDK_AVAILABLE_IN_4_6
+cairo_hint_style_t      gsk_text_node_get_hint_style            (const GskRenderNode      *node) G_GNUC_PURE;
 GDK_AVAILABLE_IN_ALL
 PangoFont *             gsk_text_node_get_font                  (const GskRenderNode      *node) G_GNUC_PURE;
 GDK_AVAILABLE_IN_ALL
diff --git a/gsk/gskrendernodeimpl.c b/gsk/gskrendernodeimpl.c
index 30ef0ff38b..8a4c003a5a 100644
--- a/gsk/gskrendernodeimpl.c
+++ b/gsk/gskrendernodeimpl.c
@@ -4336,7 +4336,10 @@ struct _GskTextNode
   GskRenderNode render_node;
 
   PangoFont *font;
-  gboolean has_color_glyphs;
+  guint has_color_glyphs : 1;
+  guint hint_metrics     : 1;
+  guint antialias        : 1;
+  guint hint_style       : 3;
 
   GdkRGBA color;
   graphene_point_t offset;
@@ -4363,6 +4366,7 @@ gsk_text_node_draw (GskRenderNode *node,
 {
   GskTextNode *self = (GskTextNode *) node;
   PangoGlyphString glyphs;
+  cairo_font_options_t *options;
 
   glyphs.num_glyphs = self->num_glyphs;
   glyphs.glyphs = self->glyphs;
@@ -4370,6 +4374,13 @@ gsk_text_node_draw (GskRenderNode *node,
 
   cairo_save (cr);
 
+  options = cairo_font_options_create ();
+  cairo_font_options_set_hint_metrics (options, self->hint_metrics ? CAIRO_HINT_METRICS_ON : 
CAIRO_HINT_METRICS_OFF);
+  cairo_font_options_set_antialias (options, self->antialias ? CAIRO_ANTIALIAS_GRAY : CAIRO_ANTIALIAS_NONE);
+  cairo_font_options_set_hint_style (options, self->hint_style);
+  cairo_set_font_options (cr, options);
+  cairo_font_options_destroy (options);
+
   gdk_cairo_set_source_rgba (cr, &self->color);
   cairo_translate (cr, self->offset.x, self->offset.y);
   pango_cairo_show_glyph_string (cr, self->font, &glyphs);
@@ -4424,25 +4435,12 @@ gsk_text_node_diff (GskRenderNode  *node1,
   gsk_render_node_diff_impossible (node1, node2, region);
 }
 
-/**
- * gsk_text_node_new:
- * @font: the `PangoFont` containing the glyphs
- * @glyphs: the `PangoGlyphString` to render
- * @color: the foreground color to render with
- * @offset: offset of the baseline
- *
- * Creates a render node that renders the given glyphs.
- *
- * Note that @color may not be used if the font contains
- * color glyphs.
- *
- * Returns: (nullable) (transfer full) (type GskTextNode): a new `GskRenderNode`
- */
-GskRenderNode *
-gsk_text_node_new (PangoFont              *font,
-                   PangoGlyphString       *glyphs,
-                   const GdkRGBA          *color,
-                   const graphene_point_t *offset)
+static GskRenderNode *
+gsk_text_node_new_internal (const cairo_font_options_t *options,
+                            PangoFont                  *font,
+                            PangoGlyphString           *glyphs,
+                            const GdkRGBA              *color,
+                            const graphene_point_t     *offset)
 {
   GskTextNode *self;
   GskRenderNode *node;
@@ -4464,6 +4462,16 @@ gsk_text_node_new (PangoFont              *font,
   self->color = *color;
   self->offset = *offset;
   self->has_color_glyphs = FALSE;
+  self->antialias = TRUE;
+  self->hint_style = CAIRO_HINT_STYLE_NONE;
+  self->hint_metrics = FALSE;
+
+  if (options)
+    {
+      self->antialias = cairo_font_options_get_antialias (options) != CAIRO_ANTIALIAS_NONE;
+      self->hint_metrics = cairo_font_options_get_hint_metrics (options) == CAIRO_HINT_METRICS_ON;
+      self->hint_style = cairo_font_options_get_hint_style (options);
+    }
 
   glyph_infos = g_malloc_n (glyphs->num_glyphs, sizeof (PangoGlyphInfo));
 
@@ -4494,6 +4502,117 @@ gsk_text_node_new (PangoFont              *font,
   return node;
 }
 
+/**
+ * gsk_text_node_new_with_font_options:
+ * @options: `cairo_font_options_t` to render with
+ * @font: the `PangoFont` containing the glyphs
+ * @glyphs: the `PangoGlyphString` to render
+ * @color: the foreground color to render with
+ * @offset: offset of the baseline
+ *
+ * Creates a render node that renders the given glyphs.
+ *
+ * Note that @color may not be used if the font contains
+ * color glyphs.
+ *
+ * Returns: (nullable) (transfer full) (type GskTextNode): a new `GskRenderNode`
+ *
+ * Since: 4.6
+ */
+GskRenderNode *
+gsk_text_node_new_with_font_options (const cairo_font_options_t *options,
+                                     PangoFont                  *font,
+                                     PangoGlyphString           *glyphs,
+                                     const GdkRGBA              *color,
+                                     const graphene_point_t     *offset)
+{
+  return gsk_text_node_new_internal (options, font, glyphs, color, offset);
+}
+
+/**
+ * gsk_text_node_new:
+ * @font: the `PangoFont` containing the glyphs
+ * @glyphs: the `PangoGlyphString` to render
+ * @color: the foreground color to render with
+ * @offset: offset of the baseline
+ *
+ * Creates a render node that renders the given glyphs.
+ *
+ * Note that @color may not be used if the font contains
+ * color glyphs.
+ *
+ * Returns: (nullable) (transfer full) (type GskTextNode): a new `GskRenderNode`
+ */
+GskRenderNode *
+gsk_text_node_new (PangoFont              *font,
+                   PangoGlyphString       *glyphs,
+                   const GdkRGBA          *color,
+                   const graphene_point_t *offset)
+{
+  return gsk_text_node_new_internal (NULL, font, glyphs, color, offset);
+}
+
+/**
+ * gsk_text_node_get_hint_metrics:
+ * @node: (type GskTextNode): a text `GskRenderNode`
+ *
+ * Retrieves whether metrics hinting is enabled for rendering.
+ *
+ * See the cairo 
[documentation](https://www.cairographics.org/manual/cairo-cairo-font-options-t.html#cairo-hint-metrics-t).
+ *
+ * Returns: whether metrics hinting is enabled
+ *
+ * Since: 4.6
+ */
+gboolean
+gsk_text_node_get_hint_metrics (const GskRenderNode *node)
+{
+  const GskTextNode *self = (const GskTextNode *) node;
+
+  return self->hint_metrics;
+}
+
+/**
+ * gsk_text_node_get_antialias:
+ * @node: (type GskTextNode): a text `GskRenderNode`
+ *
+ * Retrieves whether antialiasing is enabled for rendering.
+ *
+ * See the cairo [documentation](https://www.cairographics.org/manual/cairo-cairo-t.html#cairo-antialias-t).
+ * Note that GSK only supports grayscale antialiasing.
+ *
+ * Returns: whether antialiasing is enabled
+ *
+ * Since: 4.6
+ */
+gboolean
+gsk_text_node_get_antialias (const GskRenderNode *node)
+{
+  const GskTextNode *self = (const GskTextNode *) node;
+
+  return self->antialias;
+}
+
+/**
+ * gsk_text_node_get_hint_style:
+ * @node: (type GskTextNode): a text `GskRenderNode`
+ *
+ * Retrieves what style of font hinting is used for rendering.
+ *
+ * See the cairo 
[documentation](https://www.cairographics.org/manual/cairo-cairo-font-options-t.html#cairo-hint-style-t).
+ *
+ * Returns: what style of hinting is used
+ *
+ * Since: 4.6
+ */
+cairo_hint_style_t
+gsk_text_node_get_hint_style (const GskRenderNode *node)
+{
+  const GskTextNode *self = (const GskTextNode *) node;
+
+  return self->hint_style;
+}
+
 /**
  * gsk_text_node_get_color:
  * @node: (type GskTextNode): a text `GskRenderNode`