diff options
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | examples/text/user-font.cc | 112 |
2 files changed, 100 insertions, 18 deletions
@@ -1,5 +1,11 @@ 2008-12-11 Jonathon Jongsma <jonathon@quotidian.org> + * examples/text/user-font.cc: enhanced the UserFontFace example quite a bit so + that it shows a few different virtual functions and actually draws different + sized boxes for different characters + +2008-12-11 Jonathon Jongsma <jonathon@quotidian.org> + * cairomm/fontface.h: fix up a lot of the documentation for UserFontFace since it was redesigned to use virtual functions rather than callbacks diff --git a/examples/text/user-font.cc b/examples/text/user-font.cc index 8e5dae9..7836f5b 100644 --- a/examples/text/user-font.cc +++ b/examples/text/user-font.cc @@ -1,36 +1,98 @@ #include <cairomm/cairomm.h> #include <iostream> +#include <map> const double HEIGHT = 200.0; const double WIDTH = 400.0; const double FONT_SIZE = 64.0; const double TEXT_ORIGIN_Y = (HEIGHT / 2.0) + (FONT_SIZE / 2.0); const double TEXT_ORIGIN_X = 50.0; // arbitrary +const double GLYPH_SPACING = 0.1; + +struct GlyphBounds +{ + unsigned long glyph; + double width; + double height; +}; + +// an array that stores the bounds of the glyphs that we're going to draw +static const GlyphBounds glyphs[] = +{ + { 'c', 0.45, 0.5 }, + { 'a', 0.45, 0.5 }, + { 'i', 0.2, 0.75 }, + { 'r', 0.4, 0.5 }, + { 'o', 0.44, 0.5 }, + { 'm', 0.75, 0.5 }, + { '!', 0.2, 0.75 } +}; // A *very* simple font that just draws a box for every glyph class BoxFontFace : public Cairo::UserFontFace { public: + // Derived user font classes should have a factory method to create an object + // and return it with a RefPtr static Cairo::RefPtr<BoxFontFace> create() { return Cairo::RefPtr<BoxFontFace>(new BoxFontFace()); } virtual Cairo::ErrorStatus - render_glyph(const Cairo::RefPtr<Cairo::ScaledFont>& /*scaled_font*/, - unsigned long glyph, - const Cairo::RefPtr<Cairo::Context>& cr, - Cairo::TextExtents& /*metrics*/) + init(const Cairo::RefPtr<Cairo::ScaledFont>& /*scaled_font*/, + const Cairo::RefPtr<Cairo::Context>& /*cr*/, + Cairo::FontExtents &extents) { - std::cout << "Rendering glyph " << glyph << std::endl; - cr->set_line_width(0.05); - // FIXME: is the negative Y value correct? - cr->rectangle(0.0, 0.0, 1.0, -1.0); - cr->stroke(); + double max = 0; + for (unsigned int i = 0; i < sizeof (glyphs) / sizeof (GlyphBounds); ++i) { + if (glyphs[i].width > max) + max = glyphs[i].width; + } + // add some spacing between characters + max += GLYPH_SPACING; + extents.max_x_advance = max; + return CAIRO_STATUS_SUCCESS; + } + + virtual Cairo::ErrorStatus + unicode_to_glyph (const Cairo::RefPtr<Cairo::ScaledFont>& /*scaled_font*/, + unsigned long unicode, unsigned long& glyph) + { + glyph = 0; + // yes this is a stupid an ineffienct way to do this but we only have a few + // glyphs and this is just demonstration code + for (unsigned int i = 0; i < sizeof (glyphs) / sizeof (GlyphBounds); ++i) { + if (glyphs[i].glyph == unicode) { + // glyph 0 is often a special glyph-not-found value, so offset it by 1 + glyph = i+1; + break; + } + } + return CAIRO_STATUS_SUCCESS; + } + + virtual Cairo::ErrorStatus + render_glyph(const Cairo::RefPtr<Cairo::ScaledFont>& /*scaled_font*/, + unsigned long glyph, + const Cairo::RefPtr<Cairo::Context>& cr, + Cairo::TextExtents& metrics) + { + // check that the glyph is in our table + if (glyph >= 1 && glyph <= sizeof(glyphs)/sizeof(GlyphBounds)) { + cr->set_line_width(0.05); + // Need a negative Y value since the text origin is at the bottom left point + // and cairo's positive Y axis is down and we want to draw up + cr->rectangle(0.0, 0.0, glyphs[glyph-1].width, -glyphs[glyph-1].height); + cr->stroke(); + metrics.x_advance = glyphs[glyph-1].width + GLYPH_SPACING; + } return CAIRO_STATUS_SUCCESS; } protected: + // FontFace is a ref-counted object, so the constructor should be protected so + // it is not created without a refptr to manage it. See the create() method BoxFontFace() : UserFontFace() { } }; @@ -51,16 +113,30 @@ int main(int, char**) // draw the text cr->move_to(TEXT_ORIGIN_X, TEXT_ORIGIN_Y); cr->set_source_rgb(0.8, 0.2, 0.2); + Cairo::RefPtr<BoxFontFace> font = BoxFontFace::create(); + cr->set_font_face(font); + cr->set_font_size(FONT_SIZE); + cr->show_text("cairomm!"); - // this scope block is simply to test that the user font can still be - // drawn even after the UserFont wrapper object has been de-referenced - { - Cairo::RefPtr<BoxFontFace> font = BoxFontFace::create(); - cr->set_font_face(font); - } - + // Now show it with the toy text API to demonstrate how the glyphs match up + cr->move_to(TEXT_ORIGIN_X, TEXT_ORIGIN_Y); + cr->set_source_rgba(0.2, 0.2, 0.2, 0.3); + Cairo::RefPtr<Cairo::ToyFontFace> toy_font = + Cairo::ToyFontFace::create("Bitstream Charter", + Cairo::FONT_SLANT_NORMAL, + Cairo::FONT_WEIGHT_BOLD); + cr->set_font_face(toy_font); cr->set_font_size(FONT_SIZE); cr->show_text("cairomm!"); - surface->write_to_png("user-font.png"); - return 0; + + const char* filename = "user-font.png"; + try { + surface->write_to_png(filename); + std::cout << "Wrote Image " << filename << std::endl; + return 0; + } catch (const std::exception& e) + { + std::cout << "** Unable to write Image " << filename << std::endl; + return 1; + } } |