From 8a438c46ae91c271d7209d80b0a3e142a314379e Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Mon, 4 Apr 2022 20:38:04 -0400
Subject: [PATCH] glyphy: Update for api changes in glyphy

With this, synthetic bold fonts work as well
as they do with freetype.
---
 gsk/gl/gskglglyphylibrary.c     | 32 ++++++++++++++++++++------------
 gsk/gl/gskglrenderjob.c         |  6 +++++-
 gsk/gl/resources/glyphy.fs.glsl |  2 +-
 3 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/gsk/gl/gskglglyphylibrary.c b/gsk/gl/gskglglyphylibrary.c
index 7f6f55c8b3..ddd8dd6ccb 100644
--- a/gsk/gl/gskglglyphylibrary.c
+++ b/gsk/gl/gskglglyphylibrary.c
@@ -55,7 +55,10 @@
 #include <glyphy.h>
 
 #define TOLERANCE (1/2048.)
-#define MIN_FONT_SIZE 10
+#define MIN_FONT_SIZE 14
+#define GRID_SIZE 20 /* Per EM */
+#define ENLIGHTEN_MAX .01 /* Per EM */
+#define EMBOLDEN_MAX .024 /* Per EM */
 
 /* We split the atlas into cells of size 64x8, so the minimum number of
  * bytes we store per glyph is 2048, and an atlas of size 2048x1024 can
@@ -365,6 +368,9 @@ encode_glyph (GskGLGlyphyLibrary *self,
   guint upem = hb_face_get_upem (face);
   double tolerance = upem * tolerance_per_em;
   double faraway = (double)upem / (MIN_FONT_SIZE * M_SQRT2);
+  double unit_size = (double) upem / GRID_SIZE;
+  double enlighten_max = (double) upem * ENLIGHTEN_MAX;
+  double embolden_max = (double) upem * EMBOLDEN_MAX;
   double avg_fetch_achieved;
   GskPathBuilder *builder;
   GskPath *path, *simplified;
@@ -399,17 +405,19 @@ encode_glyph (GskGLGlyphyLibrary *self,
                                           self->acc_endpoints->len,
                                           FALSE);
 
-  if (!glyphy_arc_list_encode_blob ((gpointer)self->acc_endpoints->data,
-                                    self->acc_endpoints->len,
-                                    buffer,
-                                    buffer_len,
-                                    faraway,
-                                    4, /* UNUSED */
-                                    &avg_fetch_achieved,
-                                    output_len,
-                                    nominal_width,
-                                    nominal_height,
-                                    extents))
+  if (!glyphy_arc_list_encode_blob2 ((gpointer)self->acc_endpoints->data,
+                                     self->acc_endpoints->len,
+                                     buffer,
+                                     buffer_len,
+                                     faraway,
+                                     unit_size,
+                                     enlighten_max,
+                                     embolden_max,
+                                     &avg_fetch_achieved,
+                                     output_len,
+                                     nominal_width,
+                                     nominal_height,
+                                     extents))
     return FALSE;
 
   glyphy_extents_scale (extents, 1./upem, 1./upem);
diff --git a/gsk/gl/gskglrenderjob.c b/gsk/gl/gskglrenderjob.c
index 982cbd3b48..28a3334292 100644
--- a/gsk/gl/gskglrenderjob.c
+++ b/gsk/gl/gskglrenderjob.c
@@ -3200,6 +3200,8 @@ gsk_gl_render_job_visit_text_node_glyphy (GskGLRenderJob      *job,
   float font_scale;
   gboolean synthetic_bold;
 
+#define GRID_SIZE 20
+
   g_assert (!gsk_text_node_has_color_glyphs (node));
 
   if (!(num_glyphs = gsk_text_node_get_num_glyphs (node)))
@@ -3273,9 +3275,11 @@ gsk_gl_render_job_visit_text_node_glyphy (GskGLRenderJob      *job,
           gsk_gl_program_set_uniform1f (job->current_program,
                                         UNIFORM_GLYPHY_CONTRAST, 0,
                                         1.0);
+
+          /* 0.0208 is the value used by freetype for synthetic emboldening */
           gsk_gl_program_set_uniform1f (job->current_program,
                                         UNIFORM_GLYPHY_BOLDNESS, 0,
-                                        synthetic_bold ? 0.1 : 0.0);
+                                        synthetic_bold ? 0.0208 * GRID_SIZE : 0.0);
 
 #if 0
           gsk_gl_program_set_uniform1f (job->current_program,
diff --git a/gsk/gl/resources/glyphy.fs.glsl b/gsk/gl/resources/glyphy.fs.glsl
index 48f26f6302..0eb7ffef0d 100644
--- a/gsk/gl/resources/glyphy.fs.glsl
+++ b/gsk/gl/resources/glyphy.fs.glsl
@@ -27,7 +27,6 @@ glyph_info_decode (vec4 v)
   return gi;
 }
 
-
 float
 antialias (float d)
 {
@@ -46,6 +45,7 @@ main()
   float m = length (vec2 (length (dpdx), length (dpdy))) * SQRT2_INV;
 
   float gsdist = glyphy_sdf (p, gi.nominal_size GLYPHY_DEMO_EXTRA_ARGS);
+  gsdist -= u_boldness;
   float sdist = gsdist / m * u_contrast;
 
   if (u_outline)