netsurf/gtk/plotters.c

/*
 * Copyright 2006 Rob Kendrick <rjek@rjek.com>
 * Copyright 2005 James Bursa <bursa@users.sourceforge.net>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf 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; version 2 of the License.
 *
 * NetSurf 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, see <http://www.gnu.org/licenses/>.
 */

/** \file
 * Target independent plotting (GDK / GTK+ and Cairo implementation).
 * Can use either GDK drawing primitives (which are mostly passed straight
 * to X to process, and thus accelerated) or Cairo drawing primitives (much
 * higher quality, not accelerated).  Cairo's fast enough, so it defaults
 * to using it if it is available.  It does this by checking for the
 * CAIRO_VERSION define that the cairo headers set.
 */

#include <math.h>
#include <assert.h>
#include <gdk/gdk.h>
#include <gtk/gtk.h>

#include "utils/log.h"
#include "desktop/plotters.h"
#include "gtk/font_pango.h"
#include "gtk/plotters.h"
#include "gtk/scaffolding.h"
#include "render/font.h"
#include "desktop/options.h"
#include "gtk/options.h"
#include "gtk/bitmap.h"

#ifndef CAIRO_VERSION
#error "nsgtk requires cairo"
#endif

GtkWidget *current_widget;
GdkDrawable *current_drawable;
GdkGC *current_gc;
cairo_t *current_cr;

static GdkRectangle cliprect;
static float nsgtk_plot_scale = 1.0;

struct plotter_table plot;

/** set plotting scale factor. */
void nsgtk_plot_set_scale(float s)
{
	nsgtk_plot_scale = s;
}

/** get plotting scale factor. */
float nsgtk_plot_get_scale(void)
{
	return nsgtk_plot_scale;
}

/** Set cairo context colour to nsgtk colour. */
void nsgtk_set_colour(colour c)
{
	int r, g, b;
	GdkColor colour;

	r = c & 0xff;
	g = (c & 0xff00) >> 8;
	b = (c & 0xff0000) >> 16;

	colour.red = r | (r << 8);
	colour.green = g | (g << 8);
	colour.blue = b | (b << 8);
	colour.pixel = (r << 16) | (g << 8) | b;

	gdk_color_alloc(gdk_colormap_get_system(),
			&colour);
	gdk_gc_set_foreground(current_gc, &colour);

	cairo_set_source_rgba(current_cr, r / 255.0,
			      g / 255.0, b / 255.0, 1.0);
}

/** Plot a caret.
 *
 * @note It is assumed that the plotters have been set up.
 */
void nsgtk_plot_caret(int x, int y, int h)
{
	GdkColor colour;

	colour.red = 0;
	colour.green = 0;
	colour.blue = 0;
	colour.pixel = 0;
	gdk_color_alloc(gdk_colormap_get_system(),
			&colour);
	gdk_gc_set_foreground(current_gc, &colour);

	gdk_draw_line(current_drawable, current_gc,
		      x, y,
		      x, y + h - 1);
}

/** Set cairo context to solid plot operation. */
static inline void nsgtk_set_solid(void)
{
	double dashes = 0;
	cairo_set_dash(current_cr, &dashes, 0, 0);
}

/** Set cairo context to dotted plot operation. */
static inline void nsgtk_set_dotted(void)
{
	double cdashes[] = { 1.0, 2.0 };
	cairo_set_dash(current_cr, cdashes, 2, 0);
}

/** Set cairo context to dashed plot operation. */
static inline void nsgtk_set_dashed(void)
{
	double cdashes[] = { 8.0, 2.0 };
	cairo_set_dash(current_cr, cdashes, 2, 0);
}

/** Set clipping area for subsequent plot operations. */
static bool nsgtk_plot_clip(const struct rect *clip)
{
	cairo_reset_clip(current_cr);
	cairo_rectangle(current_cr, clip->x0, clip->y0,
			clip->x1 - clip->x0, clip->y1 - clip->y0);
	cairo_clip(current_cr);

	cliprect.x = clip->x0;
	cliprect.y = clip->y0;
	cliprect.width = clip->x1 - clip->x0;
	cliprect.height = clip->y1 - clip->y0;
	gdk_gc_set_clip_rectangle(current_gc, &cliprect);

	return true;
}


static bool nsgtk_plot_arc(int x, int y, int radius, int angle1, int angle2, const plot_style_t *style)
{
	nsgtk_set_colour(style->fill_colour);
	nsgtk_set_solid();

	cairo_set_line_width(current_cr, 1);
	cairo_arc(current_cr, x, y, radius,
		  (angle1 + 90) * (M_PI / 180),
		  (angle2 + 90) * (M_PI / 180));
	cairo_stroke(current_cr);

	return true;
}

static bool nsgtk_plot_disc(int x, int y, int radius, const plot_style_t *style)
{
	if (style->fill_type != PLOT_OP_TYPE_NONE) {
		nsgtk_set_colour(style->fill_colour);
		nsgtk_set_solid();
		cairo_set_line_width(current_cr, 0);
		cairo_arc(current_cr, x, y, radius, 0, M_PI * 2);
		cairo_fill(current_cr);
		cairo_stroke(current_cr);
	}

	if (style->stroke_type != PLOT_OP_TYPE_NONE) {
		nsgtk_set_colour(style->stroke_colour);

		switch (style->stroke_type) {
		case PLOT_OP_TYPE_SOLID: /**< Solid colour */
		default:
			nsgtk_set_solid();
			break;

		case PLOT_OP_TYPE_DOT: /**< Doted plot */
			nsgtk_set_dotted();
			break;

		case PLOT_OP_TYPE_DASH: /**< dashed plot */
			nsgtk_set_dashed();
			break;
		}

		if (style->stroke_width == 0)
			cairo_set_line_width(current_cr, 1);
		else
			cairo_set_line_width(current_cr, style->stroke_width);

		cairo_arc(current_cr, x, y, radius, 0, M_PI * 2);

		cairo_stroke(current_cr);
	}

	return true;
}

static bool nsgtk_plot_line(int x0, int y0, int x1, int y1, const plot_style_t *style)
{

	nsgtk_set_colour(style->stroke_colour);

	switch (style->stroke_type) {
	case PLOT_OP_TYPE_SOLID: /**< Solid colour */
	default:
		nsgtk_set_solid();
		break;

	case PLOT_OP_TYPE_DOT: /**< Doted plot */
		nsgtk_set_dotted();
		break;

	case PLOT_OP_TYPE_DASH: /**< dashed plot */
		nsgtk_set_dashed();
		break;
	}

	if (style->stroke_type != PLOT_OP_TYPE_NONE) {
		nsgtk_set_colour(style->stroke_colour);
	}

	if (style->stroke_width == 0)
		cairo_set_line_width(current_cr, 1);
	else
		cairo_set_line_width(current_cr, style->stroke_width);

	/* core expects horizontal and vertical lines to be on pixels, not
	 * between pixels */
	cairo_move_to(current_cr, (x0 == x1) ? x0 + 0.5 : x0,
			(y0 == y1) ? y0 + 0.5 : y0);
	cairo_line_to(current_cr, (x0 == x1) ? x1 + 0.5 : x1,
			(y0 == y1) ? y1 + 0.5 : y1);
	cairo_stroke(current_cr);

	return true;
}


static bool nsgtk_plot_rectangle(int x0, int y0, int x1, int y1, const plot_style_t *style)
{
	if (style->fill_type != PLOT_OP_TYPE_NONE) {
		nsgtk_set_colour(style->fill_colour);
		nsgtk_set_solid();

		cairo_set_line_width(current_cr, 0);
		cairo_rectangle(current_cr, x0, y0, x1 - x0, y1 - y0);
		cairo_fill(current_cr);
		cairo_stroke(current_cr);
	}

	if (style->stroke_type != PLOT_OP_TYPE_NONE) {
		nsgtk_set_colour(style->stroke_colour);

		switch (style->stroke_type) {
		case PLOT_OP_TYPE_SOLID: /**< Solid colour */
		default:
			nsgtk_set_solid();
			break;

		case PLOT_OP_TYPE_DOT: /**< Doted plot */
			nsgtk_set_dotted();
			break;

		case PLOT_OP_TYPE_DASH: /**< dashed plot */
			nsgtk_set_dashed();
			break;
		}

		if (style->stroke_width == 0)
			cairo_set_line_width(current_cr, 1);
		else
			cairo_set_line_width(current_cr, style->stroke_width);

		cairo_rectangle(current_cr, x0 + 0.5, y0 + 0.5, x1 - x0, y1 - y0);
		cairo_stroke(current_cr);
	}
	return true;
}

static bool nsgtk_plot_polygon(const int *p, unsigned int n, const plot_style_t *style)
{
	unsigned int i;

	nsgtk_set_colour(style->fill_colour);
	nsgtk_set_solid();

	cairo_set_line_width(current_cr, 0);
	cairo_move_to(current_cr, p[0], p[1]);
	for (i = 1; i != n; i++) {
		cairo_line_to(current_cr, p[i * 2], p[i * 2 + 1]);
	}
	cairo_fill(current_cr);
	cairo_stroke(current_cr);

	return true;
}




static bool nsgtk_plot_text(int x, int y, const char *text, size_t length,
		const plot_font_style_t *fstyle)
{
	return nsfont_paint(x, y, text, length, fstyle);
}



static bool nsgtk_plot_pixbuf(int x, int y, int width, int height,
			      GdkPixbuf *pixbuf, colour bg)
{
	/* XXX: This currently ignores the background colour supplied.
	 * Does this matter?
	 */

	int x0, y0, x1, y1;
	int dsrcx, dsrcy, dwidth, dheight;

	/* Bail early if we can */
	if (width == 0 || height == 0)
		/* Nothing to plot */
		return true;
	if ((x > (cliprect.x + cliprect.width)) ||
			((x + width) < cliprect.x) ||
			(y > (cliprect.y + cliprect.height)) ||
			((y + height) < cliprect.y)) {
		/* Image completely outside clip region */
		return true;	
	}

	/* Get clip rectangle / image rectangle edge differences */
	x0 = cliprect.x - x;
	y0 = cliprect.y - y;
	x1 = (x + width)  - (cliprect.x + cliprect.width);
	y1 = (y + height) - (cliprect.y + cliprect.height);

	/* Set initial draw geometry */
	dsrcx = dsrcy = 0;
	dwidth = width;
	dheight = height;

	/* Manually clip draw coordinates to area of image to be rendered */
	if (x0 > 0) {
		/* Clip left */
		dsrcx = x0;
		x += x0;
		dwidth -= x0;
	}
	if (y0 > 0) {
		/* Clip top */
		dsrcy = y0;
		y += y0;
		dheight -= y0;
	}
	if (x1 > 0) {
		/* Clip right */
		dwidth -= x1;
	}
	if (y1 > 0) {
		/* Clip bottom */
		dheight -= y1;
	}

	if (dwidth == 0 || dheight == 0)
		/* Nothing to plot */
		return true;

	/* Render the bitmap */
	if (gdk_pixbuf_get_width(pixbuf) == width &&
	    gdk_pixbuf_get_height(pixbuf) == height) {
		/* Bitmap is not scaled */
		/* Plot the bitmap */
		gdk_draw_pixbuf(current_drawable, current_gc, pixbuf,
				dsrcx, dsrcy, x, y, dwidth, dheight,
				GDK_RGB_DITHER_MAX, 0, 0);

	} else {
		/* Bitmap is scaled */
		/* Get scale factors */
		double sx = (double)width / gdk_pixbuf_get_width(pixbuf);
		double sy = (double)height / gdk_pixbuf_get_height(pixbuf);

		/* Create bitmap for scaled image portion */
		GdkPixbuf *scaled = gdk_pixbuf_new(GDK_COLORSPACE_RGB, true, 8,
				dwidth, dheight);
		/* Only scale up the portion of the bitmap that we are
		 * interested in rendering */
		gdk_pixbuf_scale(pixbuf, scaled,
				0, 0, dwidth, dheight,
				-dsrcx, -dsrcy, sx, sy,
				option_render_resample ? GDK_INTERP_BILINEAR :
				GDK_INTERP_NEAREST);
		if (!scaled)
			return false;

		/* Plot the scaled bitmap */
		gdk_draw_pixbuf(current_drawable, current_gc, scaled,
				0, 0, x, y, dwidth, dheight,
				GDK_RGB_DITHER_MAX, 0, 0);

		g_object_unref(scaled);
	}

	return true;
}

static bool nsgtk_plot_bitmap(int x, int y, int width, int height,
			      struct bitmap *bitmap, colour bg,
			      bitmap_flags_t flags)
{
	int doneheight = 0, donewidth = 0;
	GdkPixbuf *primary;
	GdkPixbuf *pretiled = NULL;

	bool repeat_x = (flags & BITMAPF_REPEAT_X);
	bool repeat_y = (flags & BITMAPF_REPEAT_Y);

	if (!(repeat_x || repeat_y)) {
		/* Not repeating at all, so just pass it on */
		primary = gtk_bitmap_get_primary(bitmap);
		return nsgtk_plot_pixbuf(x, y, width, height, primary, bg);
	}

	if (repeat_x && !repeat_y)
		pretiled = gtk_bitmap_get_pretile_x(bitmap);
	if (repeat_x && repeat_y)
		pretiled = gtk_bitmap_get_pretile_xy(bitmap);
	if (!repeat_x && repeat_y)
		pretiled = gtk_bitmap_get_pretile_y(bitmap);

	assert(pretiled != NULL);

	primary = gtk_bitmap_get_primary(bitmap);
	/* use the primary and pretiled widths to scale the w/h provided */
	width *= gdk_pixbuf_get_width(pretiled);
	width /= gdk_pixbuf_get_width(primary);
	height *= gdk_pixbuf_get_height(pretiled);
	height /= gdk_pixbuf_get_height(primary);

	if (y > cliprect.y)
		doneheight = (cliprect.y - height) + ((y - cliprect.y) % height);
	else
		doneheight = y;

	while (doneheight < (cliprect.y + cliprect.height)) {
		if (x > cliprect.x)
			donewidth = (cliprect.x - width) + ((x - cliprect.x) % width);
		else
			donewidth = x;
		while (donewidth < (cliprect.x + cliprect.width)) {
			nsgtk_plot_pixbuf(donewidth, doneheight,
					  width, height, pretiled, bg);
			donewidth += width;
			if (!repeat_x) break;
		}
		doneheight += height;
		if (!repeat_y) break;
	}

	return true;
}

static bool nsgtk_plot_path(const float *p, unsigned int n, colour fill, float width,
			    colour c, const float transform[6])
{
	unsigned int i;
	cairo_matrix_t old_ctm, n_ctm;

	if (n == 0)
		return true;

	if (p[0] != PLOTTER_PATH_MOVE) {
		LOG(("Path does not start with move"));
		return false;
	}


	/* Save CTM */
	cairo_get_matrix(current_cr, &old_ctm);

	/* Set up line style and width */
	cairo_set_line_width(current_cr, 1);
	nsgtk_set_solid();

	/* Load new CTM */
	n_ctm.xx = transform[0];
	n_ctm.yx = transform[1];
	n_ctm.xy = transform[2];
	n_ctm.yy = transform[3];
	n_ctm.x0 = transform[4];
	n_ctm.y0 = transform[5];

	cairo_set_matrix(current_cr, &n_ctm);

	/* Construct path */
	for (i = 0; i < n; ) {
		if (p[i] == PLOTTER_PATH_MOVE) {
			cairo_move_to(current_cr, p[i+1], p[i+2]);
			i += 3;
		} else if (p[i] == PLOTTER_PATH_CLOSE) {
			cairo_close_path(current_cr);
			i++;
		} else if (p[i] == PLOTTER_PATH_LINE) {
			cairo_line_to(current_cr, p[i+1], p[i+2]);
			i += 3;
		} else if (p[i] == PLOTTER_PATH_BEZIER) {
			cairo_curve_to(current_cr, p[i+1], p[i+2],
				       p[i+3], p[i+4],
				       p[i+5], p[i+6]);
			i += 7;
		} else {
			LOG(("bad path command %f", p[i]));
			/* Reset matrix for safety */
			cairo_set_matrix(current_cr, &old_ctm);
			return false;
		}
	}

	/* Restore original CTM */
	cairo_set_matrix(current_cr, &old_ctm);

	/* Now draw path */
	if (fill != NS_TRANSPARENT) {
		nsgtk_set_colour(fill);

		if (c != NS_TRANSPARENT) {
			/* Fill & Stroke */
			cairo_fill_preserve(current_cr);
			nsgtk_set_colour(c);
			cairo_stroke(current_cr);
		} else {
			/* Fill only */
			cairo_fill(current_cr);
		}
	} else if (c != NS_TRANSPARENT) {
		/* Stroke only */
		nsgtk_set_colour(c);
		cairo_stroke(current_cr);
	}

	return true;
}

/** GTK plotter table */
const struct plotter_table nsgtk_plotters = {
	.clip = nsgtk_plot_clip,
	.arc = nsgtk_plot_arc,
	.disc = nsgtk_plot_disc,
	.line = nsgtk_plot_line,
	.rectangle = nsgtk_plot_rectangle,
	.polygon = nsgtk_plot_polygon,
	.path = nsgtk_plot_path,
	.bitmap = nsgtk_plot_bitmap,
	.text = nsgtk_plot_text,
	.option_knockout = true
};