/// <summary>
/// Returns a value, which determines that the image edge is visible.
/// </summary>
/// <param name="image">The image.</param>
/// <param name="imageEdge">The image edge.</param>
/// <returns>
/// <b>true</b> - if image edge is visible.
/// <b>false</b> - if image edge is not visible.
/// </returns>
private bool GetIsImageEdgeVisible(VintasoftImage image, Vintasoft.Imaging.AnchorType imageEdge)
{
// get image viewer state for the image
Vintasoft.Imaging.UI.ImageViewerState focusedImageViewerState = ImageViewer.GetViewerState(image);
// get the visible image rectangle in image viewer
RectangleF imageVisibleRect;
if (ImageViewer.IsMultipageDisplayMode)
{
imageVisibleRect = ImageViewer.ClientRectangle;
}
else
{
imageVisibleRect = focusedImageViewerState.ImageVisibleRect;
}
// get the image rectangle in image viewer
RectangleF imageRect;
if (ImageViewer.IsMultipageDisplayMode)
{
imageRect = focusedImageViewerState.ImageBoundingBox;
}
else
{
imageRect = new RectangleF(0, 0, ImageViewer.Image.Width, ImageViewer.Image.Height);
}
if (imageRect == RectangleF.Empty)
{
return(false);
}
// get the image "anchor" line
RectangleF imageLine = RectangleF.Empty;
if (imageEdge == Vintasoft.Imaging.AnchorType.Bottom)
{
// get bottom line of image
imageLine = new RectangleF(imageRect.X, imageRect.Y + imageRect.Height - 1, imageRect.Width, 1);
}
else if (imageEdge == Vintasoft.Imaging.AnchorType.Top)
{
// get top line of image
imageLine = new RectangleF(imageRect.X, imageRect.Y, imageRect.Width, 1);
}
else if (imageEdge == Vintasoft.Imaging.AnchorType.Left)
{
// get left line of image
imageLine = new RectangleF(0, 0, 1, ImageViewer.Image.Height);
}
else if (imageEdge == Vintasoft.Imaging.AnchorType.Right)
{
// get right line of image
imageLine = new RectangleF(ImageViewer.Image.Width - 1, 0, 1, ImageViewer.Image.Height);
}
// return a value that indicates whether the visible rectangle intersects with image line
return(imageVisibleRect.IntersectsWith(imageLine));
}
/// <summary>
/// Inverts the specified anchor.
/// </summary>
/// <param name="anchor">The anchor.</param>
/// <returns>
/// The inverted value.
/// </returns>
private Vintasoft.Imaging.AnchorType Invert(Vintasoft.Imaging.AnchorType anchor)
{
switch (anchor)
{
case Vintasoft.Imaging.AnchorType.Top:
return(Vintasoft.Imaging.AnchorType.Bottom);
case Vintasoft.Imaging.AnchorType.Bottom:
return(Vintasoft.Imaging.AnchorType.Top);
case Vintasoft.Imaging.AnchorType.Left:
return(Vintasoft.Imaging.AnchorType.Right);
case Vintasoft.Imaging.AnchorType.Right:
return(Vintasoft.Imaging.AnchorType.Left);
default:
throw new NotImplementedException();
}
}
/// <summary>
/// Scrolls the image viewer.
/// </summary>
/// <param name="scrollStepSize">A scroll step size in pixels.</param>
private void Scroll(int scrollStepSize)
{
VintasoftImage image = ImageViewer.Image;
if (image == null)
{
return;
}
// determine the scroll direction
bool scrollForward = true;
_scrollAction = ScrollAction.MoveToNextPage;
Vintasoft.Imaging.AnchorType imageEdge = Vintasoft.Imaging.AnchorType.Bottom;
// if scroll step size is negative
if (scrollStepSize < 0)
{
// change the scroll direction
scrollForward = false;
_scrollAction = ScrollAction.MoveToPreviousPage;
imageEdge = Invert(imageEdge);
}
// get new scroll step size according to the focused image resolution
float newScrollStepSize = scrollStepSize * (float)image.Resolution.Vertical / 96.0f;
// if edge (top/bottom) of focused image is visible
if (GetIsImageEdgeVisible(image, imageEdge))
{
// if focused image is first image in image viewer
// and viewer must be scrolled backward
if (ImageViewer.FocusedIndex == 0 && !scrollForward)
{
return;
}
// if focused image is last in image viewer
// and viewer must be scrolled forward
if (ImageViewer.FocusedIndex >= ImageViewer.Images.Count - 1 && scrollForward)
{
return;
}
_isPageChanging = true;
int newFocusedIndex = ImageViewer.FocusedIndex;
if (scrollForward)
{
newFocusedIndex++;
}
else
{
newFocusedIndex--;
}
// if image viewer is in multipage mode
if (ImageViewer.IsMultipageDisplayMode)
{
// change focused image
ChangeFocusedImage(newFocusedIndex);
_isPageChanging = false;
}
// if image viewer is in single page mode
else
{
ImageViewer.ImageLoading += new EventHandler <ImageLoadingEventArgs>(ImageViewer_ImageLoading);
// save information about previous focused image
_previouslyFocusedImageAutoScrollPositionX = ImageViewer.ViewerState.AutoScrollPosition.X;
_previouslyFocusedImageWidth = ImageViewer.Image.Width;
// change focused index
ChangeFocusedImage(newFocusedIndex);
}
}
// get the center point of previous focused image
PointF previousFocusedImageCenterPoint = GetCenterPoint(ImageViewer.Image);
// get the scroll point of new focused image
PointF newFocusedImageScrollPoint;
switch (ImageViewer.ImageRotationAngle)
{
case 90:
newFocusedImageScrollPoint = new PointF(
previousFocusedImageCenterPoint.X + newScrollStepSize,
previousFocusedImageCenterPoint.Y);
break;
case 180:
newFocusedImageScrollPoint = new PointF(
previousFocusedImageCenterPoint.X,
previousFocusedImageCenterPoint.Y - newScrollStepSize);
break;
case 270:
newFocusedImageScrollPoint = new PointF(
previousFocusedImageCenterPoint.X - newScrollStepSize,
previousFocusedImageCenterPoint.Y);
break;
default:
newFocusedImageScrollPoint = new PointF(
previousFocusedImageCenterPoint.X,
previousFocusedImageCenterPoint.Y + newScrollStepSize);
break;
}
// scroll to the scroll point on new focused image
ImageViewer.ScrollToPoint(newFocusedImageScrollPoint,
Vintasoft.Imaging.AnchorType.Bottom |
Vintasoft.Imaging.AnchorType.Left |
Vintasoft.Imaging.AnchorType.Right |
Vintasoft.Imaging.AnchorType.Top);
_scrollAction = ScrollAction.None;
SetFocusToVisibleImage();
}