double canvas_t::set_zoom(double zoom) {
/* Limit a proposed zoom factor to sane ranges.
* Specifically the map is allowed to be no smaller than the viewport. */
canvas_goocanvas *gcanvas = static_cast<canvas_goocanvas *>(this);
/* get size of visible area in pixels and convert to meters of intended */
/* zoom by dividing by zoom (which is basically pix/m) */
const GtkAllocation &dim = widget->allocation;
double limit;
int delta;
if (dim.height < dim.width) {
limit = dim.height;
delta = gcanvas->bounds.max.y - gcanvas->bounds.min.y;
} else {
limit = dim.width;
delta = gcanvas->bounds.max.x - gcanvas->bounds.min.x;
}
limit *= 0.95 / zoom;
if (delta < limit) {
zoom /= (delta / limit);
printf("Can't zoom further out (%f)\n", zoom);
}
goo_canvas_set_scale(GOO_CANVAS(widget), zoom);
return zoom;
}
void
sheet_change_zoom (const Sheet *sheet, gdouble rate)
{
gdouble scale;
sheet->priv->zoom *= rate;
scale = goo_canvas_get_scale (GOO_CANVAS (sheet));
scale = scale * rate;
goo_canvas_set_scale (GOO_CANVAS (sheet), scale);
}
/*
* change the zoom by factor <rate>
* zoom origin when zooming in is the cursor
* zoom origin when zooming out is the center of the current viewport
* sane <rate> values are in range of [0.5 .. 2]
*/
void
sheet_change_zoom (Sheet *sheet, gdouble rate)
{
g_return_if_fail (sheet);
g_return_if_fail (IS_SHEET (sheet));
//////////////////////////////////////////////7
gdouble x, y;
gdouble rx, ry;
gdouble px, py;
gdouble dx, dy;
gdouble cx, cy;
gdouble dcx, dcy;
GtkAdjustment *hadj, *vadj;
GooCanvas *canvas;
canvas = GOO_CANVAS (sheet);
// if we scroll out, just scroll to the center
if (rate < 1.) {
goo_canvas_set_scale (canvas, rate * goo_canvas_get_scale (canvas));
return;
}
// top left corner in pixels
if (sheet_get_adjustments (sheet, &hadj, &vadj)) {
x = gtk_adjustment_get_value (hadj);
y = gtk_adjustment_get_value (vadj);
} else {
x = y = 0.;
}
// get pointer position in pixels
sheet_get_pointer_pixel (sheet, &px, &py);
// get the page size in pixels
dx = gtk_adjustment_get_page_size (hadj);
dy = gtk_adjustment_get_page_size (vadj);
// calculate the center of the widget in pixels
cx = x + dx/2;
cy = y + dy/2;
// calculate the delta between the center and the pointer in pixels
// this is required as the center is the zoom target
dcx = px - cx;
dcy = py - cy;
// increase the top left position in pixels by our calculated delta
x += dcx;
y += dcy;
//convert to canvas coords
goo_canvas_convert_from_pixels (canvas, &x, &y);
//the center of the canvas is now our cursor position
goo_canvas_scroll_to (canvas, x, y);
//calculate a correction term
//for the case that we can not scroll the pane far enough to
//compensate the whole off-due-to-wrong-center-error
rx = gtk_adjustment_get_value (hadj);
ry = gtk_adjustment_get_value (vadj);
goo_canvas_convert_from_pixels (canvas, &rx, &ry);
//the correction term in goo coordinates, to be subtracted from the backscroll distance
rx -= x;
ry -= y;
// no the center is our cursor position and we can safely call scale
goo_canvas_set_scale (canvas, rate * goo_canvas_get_scale (canvas));
// top left corner in pixels after scaling
if (sheet_get_adjustments (sheet, &hadj, &vadj)) {
x = gtk_adjustment_get_value (hadj);
y = gtk_adjustment_get_value (vadj);
} else {
x = y = 0.;
}
// not sure if the below part is required, could be zer0
NG_DEBUG ("rx %lf\n", rx);
NG_DEBUG ("ry %lf\n", ry);
NG_DEBUG ("dcx %lf\n", dcx);
NG_DEBUG ("dcy %lf\n", dcy);
NG_DEBUG ("\n\n");
// gtk_adjustment_get_page_size is constant
x -= (dcx) / sheet->priv->zoom;
y -= (dcy) / sheet->priv->zoom;
goo_canvas_convert_from_pixels (canvas, &x, &y);
goo_canvas_scroll_to (canvas, x-rx, y-ry);
gtk_widget_queue_draw (GTK_WIDGET (canvas));
}
static void
sheet_set_zoom (const Sheet *sheet, double zoom)
{
goo_canvas_set_scale (GOO_CANVAS (sheet), zoom);
sheet->priv->zoom = zoom;
}
/**
* change the zoom by factor
*
* zoom origin when zooming in is the cursor
* zoom origin when zooming out is the center of the current viewport
*
* @param sheet
* @param factor values should be in the range of [0.5 .. 2]
*/
void
sheet_change_zoom (Sheet *sheet, gdouble factor)
{
g_return_if_fail (sheet);
g_return_if_fail (IS_SHEET (sheet));
Coords adju, r, pointer, delta, center, pagesize;
GtkAdjustment *hadj = NULL, *vadj = NULL;
GooCanvas *canvas;
gboolean b = FALSE;
canvas = GOO_CANVAS (sheet);
// if we scroll out, just use the center as focus
// mouse curser centered scroll out "feels" awkward
if (factor < 1.) {
goo_canvas_set_scale (canvas, factor * goo_canvas_get_scale (canvas));
return;
}
// get pointer position in pixels
// just skip the correction if we can not get the pointer
if (!sheet_get_pointer_pixel (sheet, &pointer.x, &pointer.y)) {
goo_canvas_set_scale (canvas, factor * goo_canvas_get_scale (canvas));
g_warning ("Failed to get cursor position.");
return;
}
// top left corner in pixels
b = sheet_get_adjustments (sheet, &hadj, &vadj);
if (b) {
adju.x = gtk_adjustment_get_value (hadj);
adju.y = gtk_adjustment_get_value (vadj);
// get the page size in pixels
pagesize.x = gtk_adjustment_get_page_size (hadj);
pagesize.y = gtk_adjustment_get_page_size (vadj);
} else {
//FIXME untested codepath, check for variable space conversion
//FIXME Pixel vs GooUnits
gdouble left, right, top, bottom;
goo_canvas_get_bounds (canvas, &left, &top, &right, &bottom);
pagesize.x = bottom - top;
pagesize.y = right - left;
adju.x = adju.y = 0.;
}
// calculate the center of the widget in pixels
center.x = adju.x + pagesize.x/2.;
center.y = adju.y + pagesize.y/2.;
// calculate the delta between the center and the pointer in pixels
// this is required as the center is the zoom target
delta.x = pointer.x - center.x;
delta.y = pointer.y - center.y;
// increase the top left position in pixels by our calculated delta
adju.x += delta.x;
adju.y += delta.y;
//convert to canvas coords
goo_canvas_convert_from_pixels (canvas, &adju.x, &adju.y);
//the center of the canvas is now our cursor position
goo_canvas_scroll_to (canvas, adju.x, adju.y);
//calculate a correction term
//for the case that we can not scroll the pane far enough to
//compensate the whole off-due-to-wrong-center-error
if (b) {
r.x = gtk_adjustment_get_value (hadj);
r.y = gtk_adjustment_get_value (vadj);
goo_canvas_convert_from_pixels (canvas, &r.x, &r.y);
//the correction term in goo coordinates, to be subtracted from the backscroll distance
r.x -= adju.x;
r.y -= adju.y;
} else {
r.x = r.y = 0.;
}
// no the center is our cursor position and we can safely call scale
goo_canvas_set_scale (canvas, factor * goo_canvas_get_scale (canvas));
// top left corner in pixels after scaling
if (b) {
adju.x = gtk_adjustment_get_value (hadj);
adju.y = gtk_adjustment_get_value (vadj);
} else {
adju.x = adju.y = 0.;
}
// gtk_adjustment_get_page_size is constant before and after scale
adju.x -= (delta.x) / sheet->priv->zoom;
adju.y -= (delta.y) / sheet->priv->zoom;
goo_canvas_convert_from_pixels (canvas, &adju.x, &adju.y);
goo_canvas_scroll_to (canvas, adju.x-r.x, adju.y-r.y);
gtk_widget_queue_draw (GTK_WIDGET (canvas));
}
static void
zoom_changed (GtkAdjustment *adj, GooCanvas *canvas)
{
goo_canvas_set_scale (canvas, gtk_adjustment_get_value (adj));
}
