Re: Rendering performance on custom text view on Gdk::Drawable

[Giuseppe Penone <giuspen gmail com>]

Hi,
It seems to me to understand that you are drawing a pixbuf per byte in a drawing area.
In my opinion you should use a Gtk::TextBuffer / Gtk::TextView.
In a textbuffer you can place characters, pixbufs, widgets... anything.
Cheers,
Giuseppe.

On Mon, Jun 11, 2012 at 10:59 PM, ivar kängsepp <ivarbug gmail com> wrote:

Hi.

windows, gtkmm 2.24, mingw

I'm trying to write a hex-editor-like thingie using Gtkmm and
Gdk::Drawable and I'm having troubles getting any reasonable
performance out of it. I'm desperate for help.

Right now my code looks something like this: So far I've ended up
using prerendered characters for text.

void HexView::on_vScrl_value_changed() {
   drawingArea.queue_draw();
}

bool HexView::DrawingArea::on_expose_event(GdkEventExpose* event) {
   /* */
   Glib::RefPtr<Gdk::Window> window = get_window();
   if(window && data && numBytes) {
       /* */
       unsigned int scrlY = hexView->vScrl.get_value();
       /* */

       for(/*loop visible bytes*/) {
           /* */
           window->draw_pixbuf(char_pixbuf, 0, 0, x, y, 20, 20,
Gdk::RGB_DITHER_NONE, 0, 0);
       }
   }
   return true;
}

Gtk::TexView widget renders huge amounts of text perfectly and
scrolling is nice and fast on a 1600x1200 window. My code gives me 2
updates/second. Using Cairo with Cairo::ToyFontFace and
Cairo::Context::show_text was twice as slow.

Thanks for reading.
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