pango-markup: correct font-size setting

Previously, the font size was setting the height from baseline to
ascent (as far as I can tell).  Now it appears to be actually setting
the point size.

Also, add code to pango-blocks to log font metrics when a layout
is created.

Author: cxw42

src/writer/pango-blocks.vala

@@ -417,7 +417,8 @@ namespace My {
          * Here for convenience.  Sets wrap mode and font parameters.
          * Does not set width or text.
          *
-         * @param cr        The Cairo context with which this layout will be used
+         * @param cr        The Cairo context with which this layout will be
+         *                  used.  The device units of cr must be points.
          * @param fontname  The name of the font (a Pango family list and
          *                  style options)
          * @param fontsizeT The font size to use, in points.
@@ -432,11 +433,23 @@ namespace My {
             layout.set_wrap(Pango.WrapMode.WORD_CHAR);
 
             // Font
-            var font_description = Pango.FontDescription.from_string(
-                "%s %f".printf(fontname, fontsizeT)
-            );
+            var font_description = Pango.FontDescription.from_string(fontname);
+            font_description.set_absolute_size(c2p(fontsizeT));
             layout.set_font_description(font_description);
 
+            if(lenabled(DEBUG)) {
+                var metrics = layout.get_context().get_metrics(font_description, null);
+                ldebugo(layout, "approx char width       %f", p2i(metrics.get_approximate_char_width()));
+                ldebugo(layout, "approx digit width      %f", p2i(metrics.get_approximate_digit_width()));
+                ldebugo(layout, "ascent                  %f", p2i(metrics.get_ascent()));
+                ldebugo(layout, "descent                 %f", p2i(metrics.get_descent()));
+                // Requires Pango 1.44+ => ldebugo(layout, "line height             %f", p2i(metrics.get_height()));
+                ldebugo(layout, "strikethrough position  %f", p2i(metrics.get_strikethrough_position()));
+                ldebugo(layout, "strikethrough thickness %f", p2i(metrics.get_strikethrough_thickness()));
+                ldebugo(layout, "underline position      %f", p2i(metrics.get_underline_position()));
+                ldebugo(layout, "underline thickness     %f", p2i(metrics.get_underline_thickness()));
+            }
+
             // Paragraph
             Pango.Alignment palign = LEFT;
             switch(align) {

t/basic2para.md

@@ -8,3 +8,5 @@ nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
 incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis
 nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
 Kerning test: AVAVAVAVAV.
+
+Mxy