guideline.cpp revision 30c340c2c1ad07599daa4e97135cc3786e6a70fc
#define __SP_GUIDELINE_C__
/*
* Horizontal/vertical but can also be angled line
*
* Authors:
* Lauris Kaplinski <lauris@kaplinski.com>
* Johan Engelen
*
* Copyright (C) 2000-2002 Lauris Kaplinski
* Copyright (C) 2007 Johan Engelen
*
* Released under GNU GPL, read the file 'COPYING' for more information
*/
#include <libnr/nr-pixops.h>
#include "display-forward.h"
#include "sp-canvas-util.h"
#include "guideline.h"
static void sp_guideline_class_init(SPGuideLineClass *c);
static void sp_guideline_init(SPGuideLine *guideline);
static void sp_guideline_destroy(GtkObject *object);
static void sp_guideline_update(SPCanvasItem *item, NR::Matrix const &affine, unsigned int flags);
static void sp_guideline_render(SPCanvasItem *item, SPCanvasBuf *buf);
static double sp_guideline_point(SPCanvasItem *item, NR::Point p, SPCanvasItem **actual_item);
static void sp_guideline_drawline (SPCanvasBuf *buf, gint x0, gint y0, gint x1, gint y1, guint32 rgba);
static SPCanvasItemClass *parent_class;
GType sp_guideline_get_type()
{
static GType guideline_type = 0;
if (!guideline_type) {
static GTypeInfo const guideline_info = {
sizeof (SPGuideLineClass),
NULL, NULL,
(GClassInitFunc) sp_guideline_class_init,
NULL, NULL,
sizeof (SPGuideLine),
16,
(GInstanceInitFunc) sp_guideline_init,
NULL,
};
guideline_type = g_type_register_static(SP_TYPE_CANVAS_ITEM, "SPGuideLine", &guideline_info, (GTypeFlags) 0);
}
return guideline_type;
}
static void sp_guideline_class_init(SPGuideLineClass *c)
{
parent_class = (SPCanvasItemClass*) g_type_class_peek_parent(c);
GtkObjectClass *object_class = (GtkObjectClass *) c;
object_class->destroy = sp_guideline_destroy;
SPCanvasItemClass *item_class = (SPCanvasItemClass *) c;
item_class->update = sp_guideline_update;
item_class->render = sp_guideline_render;
item_class->point = sp_guideline_point;
}
static void sp_guideline_init(SPGuideLine *gl)
{
gl->rgba = 0x0000ff7f;
gl->normal_to_line = Geom::Point(0,1);
gl->angle = 3.14159265358979323846/2;
gl->point_on_line = Geom::Point(0,0);
gl->sensitive = 0;
}
static void sp_guideline_destroy(GtkObject *object)
{
GTK_OBJECT_CLASS(parent_class)->destroy(object);
}
static void sp_guideline_render(SPCanvasItem *item, SPCanvasBuf *buf)
{
SPGuideLine const *gl = SP_GUIDELINE (item);
sp_canvas_prepare_buffer(buf);
unsigned int const r = NR_RGBA32_R (gl->rgba);
unsigned int const g = NR_RGBA32_G (gl->rgba);
unsigned int const b = NR_RGBA32_B (gl->rgba);
unsigned int const a = NR_RGBA32_A (gl->rgba);
if (gl->is_vertical()) {
int position = gl->point_on_line[Geom::X];
if (position < buf->rect.x0 || position >= buf->rect.x1) {
return;
}
int p0 = buf->rect.y0;
int p1 = buf->rect.y1;
int step = buf->buf_rowstride;
unsigned char *d = buf->buf + 3 * (position - buf->rect.x0);
for (int p = p0; p < p1; p++) {
d[0] = NR_COMPOSEN11_1111(r, a, d[0]);
d[1] = NR_COMPOSEN11_1111(g, a, d[1]);
d[2] = NR_COMPOSEN11_1111(b, a, d[2]);
d += step;
}
} else if (gl->is_horizontal()) {
int position = gl->point_on_line[Geom::Y];
if (position < buf->rect.y0 || position >= buf->rect.y1) {
return;
}
int p0 = buf->rect.x0;
int p1 = buf->rect.x1;
int step = 3;
unsigned char *d = buf->buf + (position - buf->rect.y0) * buf->buf_rowstride;
for (int p = p0; p < p1; p++) {
d[0] = NR_COMPOSEN11_1111(r, a, d[0]);
d[1] = NR_COMPOSEN11_1111(g, a, d[1]);
d[2] = NR_COMPOSEN11_1111(b, a, d[2]);
d += step;
}
} else {
// render angled line, once intersection has been detected, draw from there.
Geom::Point parallel_to_line( gl->normal_to_line[Geom::Y],
/*should be minus, but inverted y axis*/ gl->normal_to_line[Geom::X]);
//try to intersect with left vertical of rect
double y_intersect_left = (buf->rect.x0 - gl->point_on_line[Geom::X]) * parallel_to_line[Geom::Y] / parallel_to_line[Geom::X] + gl->point_on_line[Geom::Y];
if ( (y_intersect_left >= buf->rect.y0) && (y_intersect_left <= buf->rect.y1) ) {
// intersects with left vertical!
double y_intersect_right = (buf->rect.x1 - gl->point_on_line[Geom::X]) * parallel_to_line[Geom::Y] / parallel_to_line[Geom::X] + gl->point_on_line[Geom::Y];
sp_guideline_drawline (buf, buf->rect.x0, round(y_intersect_left), buf->rect.x1, round(y_intersect_right), gl->rgba);
return;
}
//try to intersect with right vertical of rect
double y_intersect_right = (buf->rect.x1 - gl->point_on_line[Geom::X]) * parallel_to_line[Geom::Y] / parallel_to_line[Geom::X] + gl->point_on_line[Geom::Y];
if ( (y_intersect_right >= buf->rect.y0) && (y_intersect_right <= buf->rect.y1) ) {
// intersects with right vertical!
sp_guideline_drawline (buf, buf->rect.x1, round(y_intersect_right), buf->rect.x0, round(y_intersect_left), gl->rgba);
return;
}
//try to intersect with top horizontal of rect
double x_intersect_top = (buf->rect.y0 - gl->point_on_line[Geom::Y]) * parallel_to_line[Geom::X] / parallel_to_line[Geom::Y] + gl->point_on_line[Geom::X];
if ( (x_intersect_top >= buf->rect.x0) && (x_intersect_top <= buf->rect.x1) ) {
// intersects with top horizontal!
double x_intersect_bottom = (buf->rect.y1 - gl->point_on_line[Geom::Y]) * parallel_to_line[Geom::X] / parallel_to_line[Geom::Y] + gl->point_on_line[Geom::X];
sp_guideline_drawline (buf, round(x_intersect_top), buf->rect.y0, round(x_intersect_bottom), buf->rect.y1, gl->rgba);
return;
}
//try to intersect with bottom horizontal of rect
double x_intersect_bottom = (buf->rect.y1 - gl->point_on_line[Geom::Y]) * parallel_to_line[Geom::X] / parallel_to_line[Geom::Y] + gl->point_on_line[Geom::X];
if ( (x_intersect_top >= buf->rect.x0) && (x_intersect_top <= buf->rect.x1) ) {
// intersects with bottom horizontal!
sp_guideline_drawline (buf, round(x_intersect_bottom), buf->rect.y1, round(x_intersect_top), buf->rect.y0, gl->rgba);
return;
}
}
}
static void sp_guideline_update(SPCanvasItem *item, NR::Matrix const &affine, unsigned int flags)
{
SPGuideLine *gl = SP_GUIDELINE(item);
if (((SPCanvasItemClass *) parent_class)->update) {
((SPCanvasItemClass *) parent_class)->update(item, affine, flags);
}
gl->point_on_line[Geom::X] = affine[4] +0.5;
gl->point_on_line[Geom::Y] = affine[5] -0.5;
if (gl->is_horizontal()) {
sp_canvas_update_bbox (item, -1000000, gl->point_on_line[Geom::Y], 1000000, gl->point_on_line[Geom::Y] + 1);
} else if (gl->is_vertical()) {
sp_canvas_update_bbox (item, gl->point_on_line[Geom::X], -1000000, gl->point_on_line[Geom::X]+1, 1000000);
} else {
sp_canvas_update_bbox (item, -1000000, -1000000, 1000000, 1000000);
}
}
// Returns 0.0 if point is on the guideline
static double sp_guideline_point(SPCanvasItem *item, NR::Point p, SPCanvasItem **actual_item)
{
SPGuideLine *gl = SP_GUIDELINE (item);
if (!gl->sensitive) {
return NR_HUGE;
}
*actual_item = item;
Geom::Point vec(gl->normal_to_line[Geom::X], - gl->normal_to_line[Geom::Y]);
double distance = Geom::dot((p.to_2geom() - gl->point_on_line), vec);
return MAX(fabs(distance)-1, 0);
}
SPCanvasItem *sp_guideline_new(SPCanvasGroup *parent, Geom::Point point_on_line, Geom::Point normal)
{
SPCanvasItem *item = sp_canvas_item_new(parent, SP_TYPE_GUIDELINE, NULL);
SPGuideLine *gl = SP_GUIDELINE(item);
normal.normalize();
gl->normal_to_line = normal;
gl->angle = tan( -gl->normal_to_line[Geom::X] / gl->normal_to_line[Geom::Y]);
sp_guideline_set_position(gl, point_on_line);
return item;
}
void sp_guideline_set_position(SPGuideLine *gl, Geom::Point point_on_line)
{
sp_canvas_item_affine_absolute(SP_CANVAS_ITEM (gl),
NR::Matrix(NR::translate(point_on_line)));
}
void sp_guideline_set_normal(SPGuideLine *gl, Geom::Point normal_to_line)
{
gl->normal_to_line = normal_to_line;
gl->angle = tan( -normal_to_line[Geom::X] / normal_to_line[Geom::Y]);
sp_canvas_item_request_update(SP_CANVAS_ITEM (gl));
}
void sp_guideline_set_color(SPGuideLine *gl, unsigned int rgba)
{
gl->rgba = rgba;
sp_canvas_item_request_update(SP_CANVAS_ITEM(gl));
}
void sp_guideline_set_sensitive(SPGuideLine *gl, int sensitive)
{
gl->sensitive = sensitive;
}
//##########################################################
// Line rendering
#define SAFE_SETPIXEL //undefine this when it is certain that setpixel is never called with invalid params
/**
\brief This function renders a pixel on a particular buffer.
The topleft of the buffer equals
( rect.x0 , rect.y0 ) in screen coordinates
( 0 , 0 ) in setpixel coordinates
The bottomright of the buffer equals
( rect.x1 , rect,y1 ) in screen coordinates
( rect.x1 - rect.x0 , rect.y1 - rect.y0 ) in setpixel coordinates
*/
static void
sp_guideline_setpixel (SPCanvasBuf *buf, gint x, gint y, guint32 rgba)
{
#ifdef SAFE_SETPIXEL
if ( (x >= buf->rect.x0) && (x < buf->rect.x1) && (y >= buf->rect.y0) && (y < buf->rect.y1) ) {
#endif
guint r, g, b, a;
r = NR_RGBA32_R (rgba);
g = NR_RGBA32_G (rgba);
b = NR_RGBA32_B (rgba);
a = NR_RGBA32_A (rgba);
guchar * p = buf->buf + (y - buf->rect.y0) * buf->buf_rowstride + (x - buf->rect.x0) * 3;
p[0] = NR_COMPOSEN11_1111 (r, a, p[0]);
p[1] = NR_COMPOSEN11_1111 (g, a, p[1]);
p[2] = NR_COMPOSEN11_1111 (b, a, p[2]);
#ifdef SAFE_SETPIXEL
}
#endif
}
/**
\brief This function renders a line on a particular canvas buffer,
using Bresenham's line drawing function.
http://www.cs.unc.edu/~mcmillan/comp136/Lecture6/Lines.html
Coordinates are interpreted as SCREENcoordinates
*/
static void
sp_guideline_drawline (SPCanvasBuf *buf, gint x0, gint y0, gint x1, gint y1, guint32 rgba)
{
int dy = y1 - y0;
int dx = x1 - x0;
int stepx, stepy;
if (dy < 0) { dy = -dy; stepy = -1; } else { stepy = 1; }
if (dx < 0) { dx = -dx; stepx = -1; } else { stepx = 1; }
dy <<= 1; // dy is now 2*dy
dx <<= 1; // dx is now 2*dx
sp_guideline_setpixel(buf, x0, y0, rgba);
if (dx > dy) {
int fraction = dy - (dx >> 1); // same as 2*dy - dx
while (x0 != x1) {
if (fraction >= 0) {
y0 += stepy;
fraction -= dx; // same as fraction -= 2*dx
}
x0 += stepx;
fraction += dy; // same as fraction -= 2*dy
sp_guideline_setpixel(buf, x0, y0, rgba);
}
} else {
int fraction = dx - (dy >> 1);
while (y0 != y1) {
if (fraction >= 0) {
x0 += stepx;
fraction -= dy;
}
y0 += stepy;
fraction += dx;
sp_guideline_setpixel(buf, x0, y0, rgba);
}
}
}
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :