netsurf/desktop/plotters.h

152 lines
5.5 KiB
C

/*
* Copyright 2004 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 (interface).
*/
#ifndef _NETSURF_DESKTOP_PLOTTERS_H_
#define _NETSURF_DESKTOP_PLOTTERS_H_
#include <stdbool.h>
#include "css/css.h"
#include "content/content.h"
#include "desktop/plot_style.h"
#include "desktop/shape.h"
struct bitmap;
typedef unsigned long bitmap_flags_t;
#define BITMAPF_NONE 0
#define BITMAPF_REPEAT_X 1
#define BITMAPF_REPEAT_Y 2
/** Set of target specific plotting functions.
*
* The functions are:
* arc - Plots an arc, around (x,y), from anticlockwise from angle1 to
* angle2. Angles are measured anticlockwise from horizontal, in
* degrees.
* disc - Plots a circle, centered on (x,y), which is optionally filled.
* line - Plots a line from (x0,y0) to (x1,y1). Coordinates are at
* centre of line width/thickness.
* path - Plots a path consisting of cubic Bezier curves. Line colour is
* given by c and fill colour is given by fill.
* polygon - Plots a filled polygon with straight lines between points.
* The lines around the edge of the ploygon are not plotted. The
* polygon is filled with the non-zero winding rule.
* rectangle - Plots a rectangle outline. The line can be solid, dotted or
* dashed. Top left corner at (x0,y0) and rectangle has given
* width and height.
* fill - Plots a filled rectangle. Top left corner at (x0,y0), bottom
* right corner at (x1,y1). Note: (x0,y0) is inside filled area,
* but (x1,y1) is below and to the right. See diagram below.
* clip - Sets a clip rectangle for subsequent plots.
* text - Plots text. (x,y) is the coordinate of the left hand side of
* the text's baseline. The text is UTF-8 encoded. The colour, c,
* is the colour of the text. Background colour, bg, may be used
* optionally to attempt to provide anti-aliased text without
* screen reads. Font information is provided in the style.
* bitmap - Tiled plot of a bitmap image. (x,y) gives the top left
* coordinate of an explicitly placed tile. From this tile the
* image can repeat in all four directions -- up, down, left and
* right -- to the extents given by the current clip rectangle.
* The bitmap_flags say whether to tile in the x and y
* directions. If not tiling in x or y directions, the single
* image is plotted. The width and height give the dimensions
* the image is to be scaled to.
* group_start - Start of a group of objects. Used when plotter implements
* export to a vector graphics file format. (Optional.)
* group_end - End of the most recently started group. (Optional.)
* flush - Only used internally by the knockout code. Should be NULL in
* any front end display plotters or export plotters.
*
* Plotter options:
* option_knockout - Optimisation particularly for unaccelerated screen
* redraw. It tries to avoid plotting to the same area
* more than once. See desktop/knockout.c
*
* Coordinates are from top left of canvas and (0,0) is the top left grid
* denomination. If a "fill" is drawn from (0,0) to (4,3), the result is:
*
* 0 1 2 3 4 5
* +-+-+-+-+-+-
* 0 |#|#|#|#| |
* +-+-+-+-+-+-
* 1 |#|#|#|#| |
* +-+-+-+-+-+-
* 2 |#|#|#|#| |
* +-+-+-+-+-+-
* 3 | | | | | |
*/
struct plotter_table {
/* clipping operations */
bool (*clip)(const struct rect *clip);
/* shape primatives */
bool (*arc)(int x, int y, int radius, int angle1, int angle2, const plot_style_t *pstyle);
bool (*disc)(int x, int y, int radius, const plot_style_t *pstyle);
bool (*line)(int x0, int y0, int x1, int y1, const plot_style_t *pstyle);
bool (*rectangle)(int x0, int y0, int x1, int y1, const plot_style_t *pstyle);
bool (*polygon)(const int *p, unsigned int n, const plot_style_t *pstyle);
/* complex path (for SVG) */
bool (*path)(const float *p, unsigned int n, colour fill, float width,
colour c, const float transform[6]);
/* Image */
bool (*bitmap)(int x, int y, int width, int height,
struct bitmap *bitmap, colour bg,
bitmap_flags_t flags);
/**
* Text.
*
* \param x x coordinate
* \param y y coordinate
* \param text UTF-8 string to plot
* \param length length of string, in bytes
* \param fstyle plot style for this text
* \return true on success, false on error and error reported
*/
bool (*text)(int x, int y, const char *text, size_t length,
const plot_font_style_t *fstyle);
/* optional callbacks */
bool (*group_start)(const char *name); /**< optional, may be NULL */
bool (*group_end)(void); /**< optional, may be NULL */
bool (*flush)(void); /**< optional, may be NULL */
/* flags */
bool option_knockout; /**< set if knockout rendering is required */
};
/** Current plotters, must be assigned before use. */
extern struct plotter_table plot;
enum path_command {
PLOTTER_PATH_MOVE,
PLOTTER_PATH_CLOSE,
PLOTTER_PATH_LINE,
PLOTTER_PATH_BEZIER,
};
#endif