--- a/plug-ins/cairo/diacairo-renderer.c +++ a/plug-ins/cairo/diacairo-renderer.c @@ -315,6 +315,15 @@ set_fillstyle(DiaRenderer *self, FillStyle mode) DIAG_STATE(DIA_CAIRO_RENDERER (self)->cr) } +/* There is a recurring bug with pangocairo related to kerning and font scaling. + * See: https://bugzilla.gnome.org/buglist.cgi?quicksearch=341481+573261+700592 + * Rather than waiting for another fix let's try to implement the ultimate work + * around. With Pango-1.32 and HarfBuzz the kludge in Pango is gone and apparently + * substituted with a precision problem. If we now use huge fonts when talking + * to Pango and downscale these with cairo it should work with all Pango versions. + */ +#define FONT_SIZE_TWEAK (72.0) + static void set_font(DiaRenderer *self, DiaFont *font, real height) { @@ -327,7 +336,7 @@ set_font(DiaRenderer *self, DiaFont *font, real height) #ifdef HAVE_PANGOCAIRO_H /* select font and size */ - pango_font_description_set_absolute_size (pfd, (int)(size * PANGO_SCALE)); + pango_font_description_set_absolute_size (pfd, (int)(size * FONT_SIZE_TWEAK * PANGO_SCALE)); pango_layout_set_font_description (renderer->layout, pfd); pango_font_description_free (pfd); #else @@ -707,14 +716,17 @@ draw_string(DiaRenderer *self, pango_layout_iter_get_line_extents (iter, NULL, &extents); shift = alignment == ALIGN_CENTER ? PANGO_RBEARING(extents)/2 : alignment == ALIGN_RIGHT ? PANGO_RBEARING(extents) : 0; + shift /= FONT_SIZE_TWEAK; + bline /= FONT_SIZE_TWEAK; cairo_move_to (renderer->cr, pos->x - (double)shift / PANGO_SCALE, pos->y - (double)bline / PANGO_SCALE); pango_layout_iter_free (iter); } /* does this hide bug #341481? */ - pango_cairo_update_context (renderer->cr, pango_layout_get_context (renderer->layout)); - pango_layout_context_changed (renderer->layout); + cairo_scale (renderer->cr, 1.0/FONT_SIZE_TWEAK, 1.0/FONT_SIZE_TWEAK); + pango_cairo_update_layout (renderer->cr, renderer->layout); pango_cairo_show_layout (renderer->cr, renderer->layout); + /* restoring the previous scale */ cairo_restore (renderer->cr); #else /* using the 'toy API' */