[pango/round-glyphs-option: 3/3] pango-view: Add a --subpixel-positions option

[Matthias Clasen <matthiasc src gnome org>]

commit af1b7fee1b6500650682c6e4a7cb11314c9a1e91
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Aug 3 16:01:54 2019 -0400

    pango-view: Add a --subpixel-positions option
    
    This lets us explore the influence of subpixel
    positioning in various contexts without relying
    on gtk applications.

 utils/viewer-pangocairo.c | 4 ++++
 utils/viewer-render.c     | 3 +++
 utils/viewer-render.h     | 1 +
 3 files changed, 8 insertions(+)
---
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;