cairo-device.c

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/*
 * Copyright (C) 2007 Carlos Garcia Campos <carlosgc@gnome.org>
 *
 * 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, 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include <config.h>

#include <stdlib.h>
#include <gdk/gdk.h>
#ifdef HAVE_SPECTRE
#include <libspectre/spectre.h>
#endif

#include "cairo-device.h"

typedef struct {
    cairo_t *cr;

    gint xmargin;
    gint ymargin;

    gdouble xscale;
    gdouble yscale;
    
    Ulong fg;
    Ulong bg;

} DviCairoDevice;

static void
dvi_cairo_draw_glyph (DviContext  *dvi,
              DviFontChar *ch,
              int          x0,
              int          y0)
{
    DviCairoDevice  *cairo_device;
    int              x, y, w, h;
    gboolean         isbox;
    DviGlyph        *glyph;
    cairo_surface_t *surface;

    cairo_device = (DviCairoDevice *) dvi->device.device_data;

    glyph = &ch->grey;

    isbox = (glyph->data == NULL ||
             (dvi->params.flags & MDVI_PARAM_CHARBOXES) ||
             MDVI_GLYPH_ISEMPTY (glyph->data));

    x = - glyph->x + x0 + cairo_device->xmargin;
    y = - glyph->y + y0 + cairo_device->ymargin;
    w = glyph->w;
    h = glyph->h;

    surface = cairo_get_target (cairo_device->cr);
    if (x < 0 || y < 0
        || x + w > cairo_image_surface_get_width (surface)
        || y + h > cairo_image_surface_get_height (surface))
        return;

    cairo_save (cairo_device->cr);
    if (isbox) {
        cairo_rectangle (cairo_device->cr,
                 x - cairo_device->xmargin,
                 y - cairo_device->ymargin,
                 w, h);
        cairo_stroke (cairo_device->cr);
    } else {
        cairo_translate (cairo_device->cr, x, y);
        cairo_set_source_surface (cairo_device->cr,
                      (cairo_surface_t *) glyph->data,
                      0, 0);
        cairo_paint (cairo_device->cr);
    }

    cairo_restore (cairo_device->cr);
}

static void
dvi_cairo_draw_rule (DviContext *dvi,
             int         x,
             int         y,
             Uint        width,
             Uint        height,
             int         fill)
{
    DviCairoDevice *cairo_device;
    Ulong           color;

    cairo_device = (DviCairoDevice *) dvi->device.device_data;

    color = cairo_device->fg;
    
    cairo_save (cairo_device->cr);
    cairo_scale (cairo_device->cr, cairo_device->xscale, cairo_device->yscale);

    cairo_set_source_rgb (cairo_device->cr,
                  ((color >> 16) & 0xff) / 255.,
                  ((color >> 8) & 0xff) / 255.,
                  ((color >> 0) & 0xff) / 255.);

    cairo_rectangle (cairo_device->cr,
             (x + cairo_device->xmargin) / cairo_device->xscale,
             (y + cairo_device->ymargin) / cairo_device->yscale,
             width / cairo_device->xscale, height / cairo_device->yscale);
    if (fill == 0) {
        cairo_stroke (cairo_device->cr);
    } else {
        cairo_fill (cairo_device->cr);
    }

    cairo_restore (cairo_device->cr);
}

#ifdef HAVE_SPECTRE
static void
dvi_cairo_draw_ps (DviContext *dvi,
           const char *filename,
           int         x,
           int         y,
           Uint        width,
           Uint        height)
{
    DviCairoDevice       *cairo_device;
    unsigned char        *data = NULL;
    int                   row_length;
    SpectreDocument      *psdoc;
    SpectreRenderContext *rc;
    int                   w, h;
    SpectreStatus         status;
    cairo_surface_t      *image;

    cairo_device = (DviCairoDevice *) dvi->device.device_data;

    psdoc = spectre_document_new ();
    spectre_document_load (psdoc, filename);
    if (spectre_document_status (psdoc)) {
        spectre_document_free (psdoc);
        return;
    }

    spectre_document_get_page_size (psdoc, &w, &h);

    rc = spectre_render_context_new ();
    spectre_render_context_set_scale (rc,
                      (double)width / w,
                      (double)height / h);
    spectre_document_render_full (psdoc, rc, &data, &row_length);   
    status = spectre_document_status (psdoc);

    spectre_render_context_free (rc);
    spectre_document_free (psdoc);

    if (status) {
        g_warning ("Error rendering PS document %s: %s\n",
               filename, spectre_status_to_string (status));
        free (data);
        
        return;
    }

    image = cairo_image_surface_create_for_data ((unsigned char *)data,
                             CAIRO_FORMAT_RGB24,
                             width, height,
                             row_length);

    cairo_save (cairo_device->cr);

    cairo_translate (cairo_device->cr,
             x + cairo_device->xmargin,
             y + cairo_device->ymargin);
    cairo_set_source_surface (cairo_device->cr, image, 0, 0); 
    cairo_paint (cairo_device->cr);

    cairo_restore (cairo_device->cr);

    cairo_surface_destroy (image);
    free (data);
}
#endif /* HAVE_SPECTRE */

static int
dvi_cairo_alloc_colors (void  *device_data,
            Ulong *pixels,
            int    npixels,
            Ulong  fg,
            Ulong  bg,
            double gamma,
            int    density)
{
    double  frac;
    GdkColor color, color_fg;
    int     i, n;
    unsigned int alpha;

    color_fg.red = (fg >> 16) & 0xff;
    color_fg.green = (fg >> 8) & 0xff;
    color_fg.blue = (fg >> 0) & 0xff;

    n = npixels - 1;
    for (i = 0; i < npixels; i++) {
        frac = (gamma > 0) ?
            pow ((double)i / n, 1 / gamma) :
            1 - pow ((double)(n - i) / n, -gamma);
        
        color.red = frac * color_fg.red;
        color.green = frac * color_fg.green;
        color.blue = frac * color_fg.blue;
        alpha = frac * 0xFF;

        pixels[i] = (alpha << 24) + (color.red << 16) + (color.green << 8) + color.blue;
    }

    return npixels;
}

static void *
dvi_cairo_create_image (void *device_data,
            Uint  width,
            Uint  height,
            Uint  bpp)
{
    return cairo_image_surface_create (CAIRO_FORMAT_ARGB32, width, height);
}

static void
dvi_cairo_free_image (void *ptr)
{
    cairo_surface_destroy ((cairo_surface_t *)ptr);
}

static void
dvi_cairo_put_pixel (void *image, int x, int y, Ulong color)
{
    cairo_surface_t *surface;
    gint             rowstride;
    guint32         *p;

    surface = (cairo_surface_t *) image;

    rowstride = cairo_image_surface_get_stride (surface);
    p = (guint32*) (cairo_image_surface_get_data (surface) + y * rowstride + x * 4);

        /* per cairo docs, must flush before modifying outside of cairo */
        cairo_surface_flush(surface);
    *p = color;
}

static void
dvi_cairo_image_done (void *ptr)
{
        cairo_surface_mark_dirty((cairo_surface_t *)ptr);
}

static void
dvi_cairo_set_color (void *device_data, Ulong fg, Ulong bg)
{
    DviCairoDevice *cairo_device = (DviCairoDevice *) device_data;

    cairo_device->fg = fg;
    cairo_device->bg = bg;
}

/* Public methods */
void
mdvi_cairo_device_init (DviDevice *device)
{
    device->device_data = g_new0 (DviCairoDevice, 1);

    device->draw_glyph = dvi_cairo_draw_glyph;
    device->draw_rule = dvi_cairo_draw_rule;
    device->alloc_colors = dvi_cairo_alloc_colors;
    device->create_image = dvi_cairo_create_image;
    device->free_image = dvi_cairo_free_image;
    device->put_pixel = dvi_cairo_put_pixel;
        device->image_done = dvi_cairo_image_done;
    device->set_color = dvi_cairo_set_color;
#ifdef HAVE_SPECTRE
    device->draw_ps = dvi_cairo_draw_ps;
#else
    device->draw_ps = NULL;
#endif
    device->refresh = NULL;
}

void
mdvi_cairo_device_free (DviDevice *device)
{
    DviCairoDevice *cairo_device;

    cairo_device = (DviCairoDevice *) device->device_data;

    if (cairo_device->cr)
        cairo_destroy (cairo_device->cr);

    g_free (cairo_device);
}

cairo_surface_t *
mdvi_cairo_device_get_surface (DviDevice *device)
{
    DviCairoDevice *cairo_device;

    cairo_device = (DviCairoDevice *) device->device_data;

    return cairo_surface_reference (cairo_get_target (cairo_device->cr));
}

void
mdvi_cairo_device_render (DviContext* dvi)
{
    DviCairoDevice  *cairo_device;
    gint             page_width;
    gint             page_height;
    cairo_surface_t *surface;

    cairo_device = (DviCairoDevice *) dvi->device.device_data;

    if (cairo_device->cr)
        cairo_destroy (cairo_device->cr);

    page_width = dvi->dvi_page_w * dvi->params.conv + 2 * cairo_device->xmargin;
    page_height = dvi->dvi_page_h * dvi->params.vconv + 2 * cairo_device->ymargin;

    surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
                                              page_width, page_height);

    cairo_device->cr = cairo_create (surface);
        cairo_surface_destroy (surface);

        cairo_set_source_rgb (cairo_device->cr, 1., 1., 1.);
        cairo_paint (cairo_device->cr);

    mdvi_dopage (dvi, dvi->currpage);
}

void
mdvi_cairo_device_set_margins (DviDevice *device,
                   gint       xmargin,
                   gint       ymargin)
{
    DviCairoDevice *cairo_device;

    cairo_device = (DviCairoDevice *) device->device_data;

    cairo_device->xmargin = xmargin;
    cairo_device->ymargin = ymargin;
}

void
mdvi_cairo_device_set_scale (DviDevice *device,
                 gdouble    xscale,
                 gdouble    yscale)
{
    DviCairoDevice *cairo_device;

    cairo_device = (DviCairoDevice *) device->device_data;

    cairo_device->xscale = xscale;
    cairo_device->yscale = yscale;
}