cairocell.cc

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/*
  Copyright (C) 2011 Paul Davis

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <algorithm>
#include <cmath>
#include <iostream>

#include "gtkmm2ext/cairocell.h"
#include "gtkmm2ext/utils.h"

using std::string;
using std::vector;
using std::map;
using std::max;
using std::cerr;
using std::endl;
using namespace Gtkmm2ext;

static const double cairo_font_fudge = 1.5;

CairoFontDescription::CairoFontDescription (Pango::FontDescription& fd)
{
        _size = cairo_font_fudge * (fd.get_size() / PANGO_SCALE);

        switch (fd.get_style()) {
        case Pango::STYLE_NORMAL:
                _slant = Cairo::FONT_SLANT_NORMAL;
                break;
        case Pango::STYLE_OBLIQUE:
                _slant = Cairo::FONT_SLANT_OBLIQUE;
                break;
        case Pango::STYLE_ITALIC:
                _slant = Cairo::FONT_SLANT_ITALIC;
                break;
        }

        switch (fd.get_weight()) {
        case Pango::WEIGHT_ULTRALIGHT:
                _weight = Cairo::FONT_WEIGHT_NORMAL;
                break;

        case Pango::WEIGHT_LIGHT:
                _weight = Cairo::FONT_WEIGHT_NORMAL;
                break;

        case Pango::WEIGHT_NORMAL:
                _weight = Cairo::FONT_WEIGHT_NORMAL;
                break;

        case Pango::WEIGHT_SEMIBOLD:
                _weight = Cairo::FONT_WEIGHT_BOLD;
                break;

        case Pango::WEIGHT_BOLD:
                _weight = Cairo::FONT_WEIGHT_BOLD;
                break;

        case Pango::WEIGHT_ULTRABOLD:
                _weight = Cairo::FONT_WEIGHT_BOLD;
                break;

        case Pango::WEIGHT_HEAVY:
                _weight = Cairo::FONT_WEIGHT_BOLD;
                break;

        }

        face = fd.get_family();
}       

CairoCell::CairoCell (int32_t id)
        : _id (id)
        , _visible (true)
        , _xpad (0)
{
        bbox.x = 0;
        bbox.y = 0;
        bbox.width = 0;
        bbox.height = 0;
}

CairoTextCell::CairoTextCell (int32_t id, double wc, boost::shared_ptr<CairoFontDescription> font)
        : CairoCell (id)
        , _width_chars (wc)
        , _font (font)
        , y_offset (0)
        , x_offset (0)
{
}

void
CairoTextCell::set_text (const std::string& txt)
{
        _text = txt;
}

void
CairoTextCell::render (Cairo::RefPtr<Cairo::Context>& context)
{
        if (!_visible || _width_chars == 0) {
                return;
        }

        context->save ();

        context->rectangle (bbox.x, bbox.y, bbox.width, bbox.height);
        context->clip ();

        _font->apply (context);
        context->move_to (bbox.x, bbox.y + bbox.height + y_offset);
        context->show_text (_text);

        context->restore ();
}

void
CairoTextCell::set_size (Cairo::RefPtr<Cairo::Context>& context)
{
        const uint32_t lim = (uint32_t) ceil (_width_chars);
        vector<char> buf(lim+1);
        uint32_t n;
        double max_width = 0.0;
        double max_height = 0.0;
        Cairo::TextExtents ext;
        double bsum = 0;

        buf[lim] = '\0';

        _font->apply (context);

        for (int digit = 0; digit < 10; digit++) {

                for (n = 0; n < lim; ++n) {
                        buf[n] = '0' + digit; 
                }
                
                context->get_text_extents (&buf[0], ext);
                
                max_width = max (ext.width + ext.x_bearing, max_width);
                max_height = max (ext.height, max_height);
                bsum += ext.x_bearing;
        }

        /* add the average x-bearing for all digits as right hand side padding */

        bbox.width = max_width + (bsum/10.0);

        /* some fonts and some digits get their extents computed "too small", so fudge this
           by adding 2
        */
        bbox.height = max_height;
}

CairoCharCell::CairoCharCell (int32_t id, char c)
        : CairoTextCell (id, 1)
{
        _text = c;
}

void
CairoCharCell::set_size (Cairo::RefPtr<Cairo::Context>& context)
{
        Cairo::TextExtents ext;

        _font->apply (context);
        
        {
                const char* buf = "8";
                context->get_text_extents (buf, ext);
                /* same height as an "8" */
                bbox.height = ext.height;
        }

        {
                const char* buf = ":";
                context->get_text_extents (buf, ext);
                bbox.width = ext.width + (2.0 * ext.x_bearing);
                /* center vertically */
                y_offset = (ext.height - bbox.height) / 2.0;
        }
}

CairoEditableText::CairoEditableText (boost::shared_ptr<CairoFontDescription> font)
        : editing_cell (0)
        , _draw_bg (true)
        , max_cell_width (0)
        , max_cell_height (0)
        , _corner_radius (9)
        , _xpad (0)
        , _ypad (0)
{
        set_font (font);

        add_events (Gdk::POINTER_MOTION_HINT_MASK | Gdk::SCROLL_MASK | Gdk::KEY_PRESS_MASK | Gdk::KEY_RELEASE_MASK |
                    Gdk::BUTTON_PRESS_MASK | Gdk::BUTTON_RELEASE_MASK | Gdk::SCROLL_MASK);
        set_flags (Gtk::CAN_FOCUS);

        set_can_default (true);
}

CairoEditableText::~CairoEditableText ()
{
        /* we don't own cells */
}

bool
CairoEditableText::on_scroll_event (GdkEventScroll* ev)
{
        CairoCell* cell = find_cell (ev->x, ev->y);

        if (cell) {
                return scroll (ev, cell);
        }

        return false;
}

bool
CairoEditableText::on_focus_in_event (GdkEventFocus*)
{
        return false;
}

bool
CairoEditableText::on_focus_out_event (GdkEventFocus*)
{
        if (editing_cell) {
                queue_draw_cell (editing_cell);
                editing_cell = 0;
        }
        return false;
}

void
CairoEditableText::add_cell (CairoCell* cell)
{
        cells.push_back (cell);
        
        CairoTextCell* tc = dynamic_cast<CairoTextCell*>(cell);

        if (tc) {
                tc->set_font (_font);
        }

        queue_resize ();
}

void
CairoEditableText::clear_cells ()
{
        cells.clear ();
        queue_resize ();
}

void
CairoEditableText::set_width_chars (CairoTextCell* cell, uint32_t wc)
{
        if (cell) {
                cell->set_width_chars (wc);
                queue_resize ();
        }
}

void
CairoEditableText::set_text (CairoTextCell* cell, const string& text)
{
        cell->set_text (text);
        queue_draw_cell (cell);
}

bool
CairoEditableText::on_expose_event (GdkEventExpose* ev)
{
        Glib::RefPtr<Gdk::Window> win = get_window ();

        if (!win) {
                std::cerr << "CET: no window to draw on\n";
                return false;
        }

        Cairo::RefPtr<Cairo::Context> context = win->create_cairo_context();

        if (cells.empty()) {
                return true;
        }

        context->rectangle (ev->area.x, ev->area.y, ev->area.width, ev->area.height);
        context->clip ();

        Gtk::Allocation alloc = get_allocation ();
        double width = alloc.get_width();
        double height = alloc.get_height ();
                
        if (_draw_bg) {
                context->set_source_rgba (bg_r, bg_g, bg_b, bg_a);
                if (_corner_radius) {
                        rounded_rectangle (context, 0, 0, width, height, _corner_radius);
                } else {
                        context->rectangle (0, 0, width, height);
                }
                context->fill ();
        }
        
        for (CellMap::iterator i = cells.begin(); i != cells.end(); ++i) {

                CairoCell* cell = (*i);

                /* is cell inside the expose area?
                 */
                
                if (cell->intersects (ev->area)) {
                        if (cell == editing_cell) {
                                context->set_source_rgba (edit_r, edit_b, edit_g, edit_a);
                        } else {
                                context->set_source_rgba (r, g, b, a);
                        }

                        cell->render (context);
                }
        }

        return true;
}

void
CairoEditableText::queue_draw_cell (CairoCell* cell)
{
        Glib::RefPtr<Gdk::Window> win = get_window();

        if (!win) {
                return;
        }

        Gdk::Rectangle r;

        r.set_x (cell->x());
        r.set_y (cell->y());
        r.set_width (cell->width());
        r.set_height (cell->height());

        Gdk::Region rg (r);
        win->invalidate_region (rg, true);
}

CairoCell*
CairoEditableText::find_cell (uint32_t x, uint32_t y)
{
        for (CellMap::iterator i = cells.begin(); i != cells.end(); ++i) {
                if ((*i)->covers (x, y)) {
                        return (*i);
                }
        }

        return 0;
}

bool
CairoEditableText::on_button_press_event (GdkEventButton* ev)
{
        CairoCell* cell = find_cell (ev->x, ev->y);
        return button_press (ev, cell);
}

bool
CairoEditableText::on_button_release_event (GdkEventButton* ev)
{
        CairoCell* cell = find_cell (ev->x, ev->y);
        return button_release (ev, cell);
}

void
CairoEditableText::start_editing (CairoCell* cell)
{
        stop_editing ();

        if (cell) {
                editing_cell = cell;
                queue_draw_cell (cell);
                grab_focus ();
        }
}

void
CairoEditableText::stop_editing ()
{
        if (editing_cell) {
                queue_draw_cell (editing_cell);
                editing_cell = 0;
        }
}

void
CairoEditableText::set_cell_sizes ()
{
        Glib::RefPtr<Gdk::Window> win = get_window();

        if (!win) {
                return;
        }
        
        Cairo::RefPtr<Cairo::Context> context = win->create_cairo_context();
        
        if (!context) {
                return;
        }

        for (CellMap::iterator i = cells.begin(); i != cells.end(); ++i) {
                (*i)->set_size (context);
        }
}

void
CairoEditableText::on_size_request (GtkRequisition* req)
{
        set_cell_sizes ();

        max_cell_width = 0;
        max_cell_height = 0;
        
        for (CellMap::iterator i = cells.begin(); i != cells.end(); ++i) {
                max_cell_width += (*i)->width();
                max_cell_height = std::max ((double) (*i)->height(), max_cell_height);
        }

        req->width = max_cell_width;
        req->height = max_cell_height;
}

void
CairoEditableText::on_size_allocate (Gtk::Allocation& alloc)
{
        Misc::on_size_allocate (alloc);

        /* position each cell so that its centered in the allocated space
         */

        double x = (alloc.get_width() - max_cell_width)/2.0;
        double y = (alloc.get_height() - max_cell_height)/2.0;

        CellMap::iterator i = cells.begin();

        while (i != cells.end()) {
                CairoCell* cell = (*i);

                cell->set_position (x, y);
                x += cell->width ();

                if (++i != cells.end()) {
                        /* only add cell padding intra-cellularly */
                        x += cell->xpad();
                } else {
                        break;
                }
        }
}

void
CairoEditableText::set_font (Pango::FontDescription& fd)
{
        boost::shared_ptr<CairoFontDescription> cd (new CairoFontDescription (fd));
        set_font (cd);
}

void
CairoEditableText::set_font (boost::shared_ptr<CairoFontDescription> fd)
{
        for (CellMap::iterator i = cells.begin(); i != cells.end(); ++i) {
                CairoTextCell* tc = dynamic_cast<CairoTextCell*>(*i);
                if (tc && (!tc->font() || tc->font() == _font)) {
                        tc->set_font (fd);
                }
        }

        _font = fd;

        queue_resize ();
        queue_draw ();
}