Warn on FreeType missing glyphs.

anntzer · anntzer · commit cc744f54214c · 2018-11-14T11:41:13.000+01:00
diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
@@ -16,6 +16,7 @@
 import sys
 import time
 import types
+import warnings
 import zlib
 
 import numpy as np
@@ -937,8 +938,13 @@ def get_char_width(charcode):
                     s, flags=LOAD_NO_SCALE | LOAD_NO_HINTING).horiAdvance
                 return cvt(width)
 
-            widths = [get_char_width(charcode)
-                      for charcode in range(firstchar, lastchar+1)]
+            with warnings.catch_warnings():
+                # Ignore 'Required glyph missing from current font' warning
+                # from ft2font: here we're just builting the widths table, but
+                # the missing glyphs may not even be used in the actual string.
+                warnings.filterwarnings("ignore")
+                widths = [get_char_width(charcode)
+                          for charcode in range(firstchar, lastchar+1)]
             descriptor['MaxWidth'] = max(widths)
 
             # Make the "Differences" array, sort the ccodes < 255 from
diff --git a/src/ft2font.cpp b/src/ft2font.cpp
@@ -8,6 +8,7 @@
 
 #include "ft2font.h"
 #include "mplutils.h"
+#include "py_exceptions.h"
 
 #ifndef M_PI
 #define M_PI 3.14159265358979323846264338328
@@ -162,9 +163,24 @@ FT2Image::draw_rect_filled(unsigned long x0, unsigned long y0, unsigned long x1,
 
 inline double conv(long v)
 {
-    return double(v) / 64.0;
+    return v / 64.;
 }
 
+static FT_UInt ft_get_char_index_or_warn(FT_Face face, FT_ULong charcode)
+{
+    FT_UInt glyph_index = FT_Get_Char_Index(face, charcode);
+    if (!glyph_index) {
+        PyErr_WarnFormat(NULL, 1, "Glyph %lu missing from current font.", charcode);
+        // Apparently PyErr_WarnFormat returns 0 even if the exception propagates
+        // due to running with -Werror, so check the error flag directly instead.
+        if (PyErr_Occurred()) {
+            throw py::exception();
+        }
+    }
+    return glyph_index;
+}
+
+
 int FT2Font::get_path_count()
 {
     // get the glyph as a path, a list of (COMMAND, *args) as described in matplotlib.path
@@ -610,7 +626,7 @@ void FT2Font::set_text(
         FT_BBox glyph_bbox;
         FT_Pos last_advance;
 
-        glyph_index = FT_Get_Char_Index(face, codepoints[n]);
+        glyph_index = ft_get_char_index_or_warn(face, codepoints[n]);
 
         // retrieve kerning distance and move pen position
         if (use_kerning && previous && glyph_index) {
@@ -663,7 +679,8 @@ void FT2Font::set_text(
 
 void FT2Font::load_char(long charcode, FT_Int32 flags)
 {
-    int error = FT_Load_Char(face, (unsigned long)charcode, flags);
+    FT_UInt glyph_index = ft_get_char_index_or_warn(face, (FT_ULong)charcode);
+    int error = FT_Load_Glyph(face, glyph_index, flags);
 
     if (error) {
         throw std::runtime_error("Could not load charcode");
diff --git a/src/ft2font_wrapper.cpp b/src/ft2font_wrapper.cpp
@@ -998,8 +998,8 @@ static PyObject *PyFT2Font_get_char_index(PyFT2Font *self, PyObject *args, PyObj
 const char *PyFT2Font_get_sfnt__doc__ =
     "get_sfnt(name)\n"
     "\n"
-    "Get all values from the SFNT names table.  Result is a dictionary whose"
-    "key is the platform-ID, ISO-encoding-scheme, language-code, and"
+    "Get all values from the SFNT names table.  Result is a dictionary whose "
+    "key is the platform-ID, ISO-encoding-scheme, language-code, and "
     "description.\n";
 
 static PyObject *PyFT2Font_get_sfnt(PyFT2Font *self, PyObject *args, PyObject *kwds)
