func draw_selections(viewp, bufferp, crp unsafe.Pointer, mark_pairs []unsafe.Pointer) { view := (*C.GtkTextView)(viewp) buffer := (*C.GtkTextBuffer)(bufferp) cr := (*C.cairo_t)(crp) var alloc C.GtkAllocation C.gtk_widget_get_allocation((*C.GtkWidget)(viewp), &alloc) n := len(mark_pairs) var start_mark, stop_mark *C.GtkTextMark var location C.GdkRectangle var iter C.GtkTextIter var x, y C.gint var dx, dy C.double for i := 0; i < n; i += 2 { start_mark = (*C.GtkTextMark)(mark_pairs[i]) C.gtk_text_buffer_get_iter_at_mark(buffer, &iter, start_mark) C.gtk_text_view_get_iter_location(view, &iter, &location) C.gtk_text_view_buffer_to_window_coords(view, C.GTK_TEXT_WINDOW_WIDGET, C.gint(location.x), C.gint(location.y), &x, &y) if C.int(x) > alloc.width || C.int(y) > alloc.height || x < 0 || y < 0 { continue } dx = C.double(x) dy = C.double(y) C.cairo_set_source_rgb(cr, 1, 0, 0) C.cairo_move_to(cr, dx, dy) C.cairo_set_line_width(cr, 2) C.cairo_line_to(cr, dx+6, dy) C.cairo_stroke(cr) C.cairo_move_to(cr, dx, dy) C.cairo_set_line_width(cr, 1) C.cairo_line_to(cr, dx, dy+C.double(location.height)) C.cairo_stroke(cr) stop_mark = (*C.GtkTextMark)(mark_pairs[i+1]) C.gtk_text_buffer_get_iter_at_mark(buffer, &iter, stop_mark) C.gtk_text_view_get_iter_location(view, &iter, &location) C.gtk_text_view_buffer_to_window_coords(view, C.GTK_TEXT_WINDOW_WIDGET, C.gint(location.x), C.gint(location.y), &x, &y) if C.int(x) > alloc.width || C.int(y) > alloc.height || x < 0 || y < 0 { continue } dx = C.double(x) dy = C.double(y) C.cairo_set_source_rgb(cr, 0, 1, 0) C.cairo_move_to(cr, dx, dy) C.cairo_set_line_width(cr, 1) C.cairo_line_to(cr, dx, dy+C.double(location.height)) C.cairo_stroke(cr) C.cairo_move_to(cr, dx, dy+C.double(location.height)) C.cairo_set_line_width(cr, 2) C.cairo_line_to(cr, dx-6, dy+C.double(location.height)) C.cairo_stroke(cr) } }
// Draw given poligon path, automatically closing first and last point func (i *Image) DrawPoly(points ...float64) { C.cairo_move_to(i.Ctx, C.double(points[0]), C.double(points[1])) for j := 2; j < len(points); j += 2 { C.cairo_line_to(i.Ctx, C.double(points[j]), C.double(points[j+1])) } C.cairo_close_path(i.Ctx) }
func (self *Surface) LineTo(x, y float64) { C.cairo_line_to(self.context, C.double(x), C.double(y)) }
// LineTo is a wrapper around cairo_line_to(). func (v *Context) LineTo(x, y float64) { C.cairo_line_to(v.native(), C.double(x), C.double(y)) }
//LineTo adds a line to the path from the current point to p in user space //coordinates. // //If there is no current point, LineTo will behave as if preceded by a call //to MoveTo(p) // //Originally cairo_line_to. func (c *Context) LineTo(p Point) *Context { x, y := p.c() C.cairo_line_to(c.c, x, y) return c }