The R Project SVN R

/*
 *  R : A Computer Langage for Statistical Data Analysis
 *  Copyright (C) 1998-1999   Lyndon Drake
 *                            and the R Development Core Team
 *
 *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "gdkrotated.h"

#include <math.h>



void gdk_draw_text_rot(GdkDrawable *drawable,
               GdkFont *font,
               GdkGC *gc,
               int x, int y,
               int maxx, int maxy,
               const gchar *text,
               gint text_length,
               double angle)
{
    GdkColor black, white;
    GdkPixmap *pixmap;
    GdkGC *rotgc;
    GdkImage *image;

    int lbearing, rbearing, width, ascent, descent, height;
    int dx, dy;
    int i, j, mini, minj, maxi, maxj;

    double sintheta, costheta;

    /* sanity check */
    if((text == NULL) || (*text == '\0'))
    return;

    /* shortcut horizontal text */
    if(angle == 0.0) {
    gdk_draw_text(drawable, font, gc, x, y, text, text_length);
    }
    else {
    /* text metrics */
    gdk_text_extents(font, text, text_length,
             &lbearing, &rbearing,
             &width, &ascent, &descent);
    
    height = ascent + descent;
    
    /* draw text into pixmap */
    pixmap = gdk_pixmap_new(drawable, width, height, 1);
    rotgc = gdk_gc_new(pixmap);
    gdk_gc_set_font(rotgc, font);

    white.pixel = gdk_rgb_xpixel_from_rgb(0xffffffff);
    black.pixel = gdk_rgb_xpixel_from_rgb(0);

    gdk_gc_set_foreground(rotgc, &white);
    gdk_draw_rectangle (pixmap, rotgc, 1, 0, 0, width, height);

    gdk_gc_set_foreground(rotgc, &black);
    gdk_draw_text(pixmap, font, rotgc, 0, ascent, text, text_length);
    image = gdk_image_get(pixmap, 0, 0, width, height); 

    /* precalc cos/sin of angle */
    /* the floor(x * 1000.0 + 0.5) / 1000.0 is a hack to round things off */
    costheta = floor(cos(angle) * 1000.0 + 0.5) / 1000.0;
    sintheta = floor(sin(angle) * 1000.0 + 0.5) / 1000.0;

    /* calculate bounding box for i and j iteration */
    mini = maxi = floor((double)(0 - ascent) * sintheta) + x;
    minj = maxj = floor((double)(0 - ascent) * costheta) + y;

    i = floor((double)width * costheta + (double)(height - ascent) * sintheta) + x;
    j = floor(- (double)width * sintheta + (double)(height - ascent) * costheta) + y;
    if(i < mini) mini = i;
    if(i > maxi) maxi = i;
    if(j < minj) minj = j;
    if(j > maxj) maxj = j;

    i = floor((double)(height - ascent) * sintheta) + x;
    j = floor((double)(height - ascent) * costheta) + y;
    if(i < mini) mini = i;
    if(i > maxi) maxi = i;
    if(j < minj) minj = j;
    if(j > maxj) maxj = j;

    i = floor((double)width * costheta + (double)(0 - ascent) * sintheta) + x;
    j = floor(- (double)width * sintheta + (double)(0 - ascent) * costheta) + y;
    if(i < mini) mini = i;
    if(i > maxi) maxi = i;
    if(j < minj) minj = j;
    if(j > maxj) maxj = j;

    maxi++; maxj++;

    if(mini < 0) mini = 0;
    if(maxi > maxx) maxi = maxx;
    if(minj < 0) minj = 0;
    if(maxj > maxy) maxj = maxy;

    /* copy pixels */
    for(j = minj; j < maxj; j++) {
        for(i = mini; i < maxi; i++) {
        dx = floor((double)(i - x) * costheta - (double)(j - y) * sintheta);
        dy = floor((double)(i - x) * sintheta + (double)(j - y) * costheta) + ascent;
        
        if((dx >= 0) && (dx < width) && (dy >= 0) && (dy < height) &&
           (gdk_image_get_pixel(image, dx, dy) == black.pixel)) {
            gdk_draw_point(drawable, gc, i, j);
        }
        }
    }

    /* clean up */
    gdk_pixmap_unref(pixmap);
    gdk_gc_unref(rotgc);
    }
}