private void Recalculate(bool doLayout)
{
if (!IsHandleCreated)
{
return;
}
Size canvas = canvas_size;
Size client = ClientSize;
canvas.Width += auto_scroll_margin.Width;
canvas.Height += auto_scroll_margin.Height;
int right_edge = client.Width;
int bottom_edge = client.Height;
int prev_right_edge;
int prev_bottom_edge;
bool hscroll_visible;
bool vscroll_visible;
do
{
prev_right_edge = right_edge;
prev_bottom_edge = bottom_edge;
if ((force_hscroll_visible || (canvas.Width > right_edge && auto_scroll)) && client.Width > 0)
{
hscroll_visible = true;
bottom_edge = client.Height - SystemInformation.HorizontalScrollBarHeight;
}
else
{
hscroll_visible = false;
bottom_edge = client.Height;
}
if ((force_vscroll_visible || (canvas.Height > bottom_edge && auto_scroll)) && client.Height > 0)
{
vscroll_visible = true;
right_edge = client.Width - SystemInformation.VerticalScrollBarWidth;
}
else
{
vscroll_visible = false;
right_edge = client.Width;
}
} while (right_edge != prev_right_edge || bottom_edge != prev_bottom_edge);
if (right_edge < 0)
{
right_edge = 0;
}
if (bottom_edge < 0)
{
bottom_edge = 0;
}
Rectangle hscroll_bounds;
Rectangle vscroll_bounds;
hscroll_bounds = new Rectangle(0, client.Height - SystemInformation.HorizontalScrollBarHeight,
ClientRectangle.Width, SystemInformation.HorizontalScrollBarHeight);
vscroll_bounds = new Rectangle(client.Width - SystemInformation.VerticalScrollBarWidth, 0,
SystemInformation.VerticalScrollBarWidth, ClientRectangle.Height);
/* the ScrollWindow calls here are needed
* because (this explanation sucks):
*
* when we transition from having a scrollbar to
* not having one, we won't receive a scrollbar
* moved (value changed) event, so we need to
* manually scroll the canvas.
*
* if you can fix this without requiring the
* ScrollWindow calls, pdb and toshok will each
* pay you $5.
*/
if (!vscrollbar.Visible)
{
vscrollbar.Value = vscrollbar.Minimum;
}
if (!hscrollbar.Visible)
{
hscrollbar.Value = hscrollbar.Minimum;
}
/* Manually setting the size of the thumb should be done before
* the other assignments */
if (hscroll_visible)
{
hscrollbar.manual_thumb_size = right_edge;
hscrollbar.LargeChange = right_edge;
hscrollbar.SmallChange = 5;
hscrollbar.Maximum = canvas.Width - 1;
}
else
{
if (hscrollbar != null && hscrollbar.VisibleInternal)
{
ScrollWindow(-scroll_position.X, 0);
}
scroll_position.X = 0;
}
if (vscroll_visible)
{
vscrollbar.manual_thumb_size = bottom_edge;
vscrollbar.LargeChange = bottom_edge;
vscrollbar.SmallChange = 5;
vscrollbar.Maximum = canvas.Height - 1;
}
else
{
if (vscrollbar != null && vscrollbar.VisibleInternal)
{
ScrollWindow(0, -scroll_position.Y);
}
scroll_position.Y = 0;
}
if (hscroll_visible && vscroll_visible)
{
hscroll_bounds.Width -= SystemInformation.VerticalScrollBarWidth;
vscroll_bounds.Height -= SystemInformation.HorizontalScrollBarHeight;
sizegrip.Bounds = new Rectangle(hscroll_bounds.Right,
vscroll_bounds.Bottom,
SystemInformation.VerticalScrollBarWidth,
SystemInformation.HorizontalScrollBarHeight);
}
SuspendLayout();
hscrollbar.SetBounds(hscroll_bounds.X, hscroll_bounds.Y, hscroll_bounds.Width, hscroll_bounds.Height, BoundsSpecified.All);
hscrollbar.Visible = hscroll_visible;
if (hscrollbar.Visible)
{
XplatUI.SetZOrder(hscrollbar.Handle, IntPtr.Zero, true, false);
}
vscrollbar.SetBounds(vscroll_bounds.X, vscroll_bounds.Y, vscroll_bounds.Width, vscroll_bounds.Height, BoundsSpecified.All);
vscrollbar.Visible = vscroll_visible;
if (vscrollbar.Visible)
{
XplatUI.SetZOrder(vscrollbar.Handle, IntPtr.Zero, true, false);
}
UpdateSizeGripVisible();
ResumeLayout(doLayout);
// We should now scroll the active control into view,
// the funny part is that ScrollableControl does not have
// the concept of active control.
ContainerControl container = this as ContainerControl;
if (container != null && container.ActiveControl != null)
{
ScrollControlIntoView(container.ActiveControl);
}
}
