/// <summary>
/// Updates vertical and horizontal scrollbars to correspond to the current visible and canvas
/// dimensions</summary>
/// <param name="vScrollBar">Vertical ScrollBar, or null if none</param>
/// <param name="hScrollBar">Horizontal ScrollBar, or null if none</param>
protected virtual void UpdateScrollBars(VScrollBar vScrollBar, HScrollBar hScrollBar)
{
Size canvasSizeInPixels = GetCanvasSize();
RectangleF clientRect = VisibleClientRectangle;
Size viewSizeInPixels = new Size((int)clientRect.Width, (int)clientRect.Height);
WinFormsUtil.UpdateScrollbars(
vScrollBar,
hScrollBar,
viewSizeInPixels,
canvasSizeInPixels);
}
private void UpdateScrollbars()
{
if (m_updatingScrollbars)
{
return;
}
try
{
m_updatingScrollbars = true;
// get view rectangle in Windows client coordinates
Rectangle viewRect = AdaptedControl.ClientRectangle;
// get canvas bounds in Windows client coordinates
Rectangle canvasRect = m_canvasAdapter.Bounds; // start with world coordinates
PointF scale = m_transformAdapter.Scale;
// Calculate the negation of the translation, by allowing the translation to range far
// enough so that the edge of the canvas can get to the center of the screen.
int minTransX = (int)(canvasRect.X * scale.X - viewRect.Width * 0.5f);
int minTransY = (int)(canvasRect.Y * scale.Y - viewRect.Height * 0.5f);
int maxTransX = (int)(canvasRect.Right * scale.X - viewRect.Width * 0.5f);
int maxTransY = (int)(canvasRect.Bottom * scale.Y - viewRect.Height * 0.5f);
canvasRect = new Rectangle(minTransX, minTransY, maxTransX - minTransX, maxTransY - minTransY);
WinFormsUtil.UpdateScrollbars(
m_vScrollBar,
m_hScrollBar,
viewRect,
canvasRect);
// Set the scrollbars' values to be the negation of the translation.
if (!m_hScrollBar.Capture && !m_vScrollBar.Capture)
{
PointF translation = m_transformAdapter.Translation;
m_hScrollBar.Value = Math.Min(Math.Max(m_hScrollBar.Minimum, -(int)translation.X), m_hScrollBar.Maximum);
m_vScrollBar.Value = Math.Min(Math.Max(m_vScrollBar.Minimum, -(int)translation.Y), m_vScrollBar.Maximum);
}
}
finally
{
m_updatingScrollbars = false;
}
}
private Rectangle UpdateScrollbars()
{
// get canvas size, in client coordinates
Size canvasSize = m_canvasAdapter.Bounds.Size;
PointF scale = m_transformAdapter.Scale;
Size canvasSizeInPixels = new Size(
(int)(canvasSize.Width * scale.X),
(int)(canvasSize.Height * scale.Y));
// get window bounds to allow for scrollbars without obscuring any of canvas
Rectangle windowBounds = AdaptedControl.ClientRectangle;
try
{
m_updatingScrollbars = true;
WinFormsUtil.UpdateScrollbars(
m_vScrollBar,
m_hScrollBar,
windowBounds.Size,
canvasSizeInPixels);
if (!m_hScrollBar.Capture &&
!m_vScrollBar.Capture)
{
PointF translation = m_transformAdapter.Translation;
m_hScrollBar.Value = Math.Min(Math.Max(m_hScrollBar.Minimum, -(int)translation.X), m_hScrollBar.Maximum);
m_vScrollBar.Value = Math.Min(Math.Max(m_vScrollBar.Minimum, -(int)translation.Y), m_vScrollBar.Maximum);
}
}
finally
{
m_updatingScrollbars = false;
}
return(windowBounds);
}
public void TestUpdateScrollbars()
{
var vBar = new VScrollBar();
var hBar = new HScrollBar();
Rectangle visibleArea, contentArea, finalVisible;
// Visible area surrounds content area, so scrollbars are not required
contentArea = new Rectangle(0, 0, 100, 100);
visibleArea = contentArea;
visibleArea.Inflate(20, 20);
finalVisible = WinFormsUtil.UpdateScrollbars(vBar, hBar, visibleArea, contentArea);
Assert.False(vBar.Visible);
Assert.False(hBar.Visible);
Assert.AreEqual(visibleArea, finalVisible);
// Visible area is inside content area, so scrollbars are required
contentArea = new Rectangle(0, 0, 100, 100);
visibleArea = contentArea;
visibleArea.Inflate(-20, -20);
finalVisible = WinFormsUtil.UpdateScrollbars(vBar, hBar, visibleArea, contentArea);
Assert.True(vBar.Visible);
Assert.True(hBar.Visible);
Assert.True(finalVisible.Width < visibleArea.Width);
Assert.True(finalVisible.Height < visibleArea.Height);
Assert.True(hBar.Minimum == contentArea.Left);
Assert.True(hBar.Maximum == contentArea.Right);
Assert.True(vBar.Minimum == contentArea.Top);
Assert.True(vBar.Maximum == contentArea.Bottom);
// Visible area surrounds content area, so scrollbars are not required. Uses negative coordinates.
contentArea = new Rectangle(-1000, 0, 100, 100);
visibleArea = contentArea;
visibleArea.Inflate(20, 20);
finalVisible = WinFormsUtil.UpdateScrollbars(vBar, hBar, visibleArea, contentArea);
Assert.False(vBar.Visible);
Assert.False(hBar.Visible);
Assert.AreEqual(visibleArea, finalVisible);
// Visible area is inside content area, so scrollbars are required. Uses negative coordinates.
contentArea = new Rectangle(-1000, 0, 100, 100);
visibleArea = contentArea;
visibleArea.Inflate(-20, -20);
finalVisible = WinFormsUtil.UpdateScrollbars(vBar, hBar, visibleArea, contentArea);
Assert.True(vBar.Visible);
Assert.True(hBar.Visible);
Assert.True(finalVisible.Width < visibleArea.Width);
Assert.True(finalVisible.Height < visibleArea.Height);
Assert.True(hBar.Minimum == contentArea.Left);
Assert.True(hBar.Maximum == contentArea.Right);
Assert.True(vBar.Minimum == contentArea.Top);
Assert.True(vBar.Maximum == contentArea.Bottom);
// Visible area is to the left of content area, so scrollbars are required
contentArea = new Rectangle(1000, 0, 100, 100);
visibleArea = new Rectangle(0, 0, 100, 100);
finalVisible = WinFormsUtil.UpdateScrollbars(vBar, hBar, visibleArea, contentArea);
Assert.True(vBar.Visible);
Assert.True(hBar.Minimum == visibleArea.Left);
Assert.True(hBar.Maximum == contentArea.Right);
Assert.True(vBar.Minimum == contentArea.Top);
Assert.True(vBar.Maximum == contentArea.Bottom);
// Zero visible area!
contentArea = new Rectangle(1000, 1000, 100, 100);
visibleArea = new Rectangle();
WinFormsUtil.UpdateScrollbars(vBar, hBar, visibleArea, contentArea);
Assert.True(vBar.Visible);
Assert.True(hBar.Visible);
// Zero content area, off screen.
visibleArea = new Rectangle(1000, 1000, 100, 100);
contentArea = new Rectangle(10, 20, 0, 0);
WinFormsUtil.UpdateScrollbars(vBar, hBar, visibleArea, contentArea);
Assert.True(vBar.Visible);
Assert.True(hBar.Visible);
// Zero content area, on screen.
visibleArea = new Rectangle(1000, 1000, 100, 100);
contentArea = new Rectangle(1000, 1000, 0, 0);
WinFormsUtil.UpdateScrollbars(vBar, hBar, visibleArea, contentArea);
Assert.False(vBar.Visible);
Assert.False(hBar.Visible);
// The scrollbars are optional.
contentArea = new Rectangle(-1000, 0, 100, 100);
visibleArea = contentArea;
visibleArea.Inflate(-20, -20);
finalVisible = WinFormsUtil.UpdateScrollbars(null, null, visibleArea, contentArea);
Assert.AreEqual(visibleArea, finalVisible);
}