private void CalculateCanvas()
{
if (canvasDirty == TCanvasDirtyness.Clean)
{
return;
}
int start = 1, end = PageCount;
//If we are in a mode which doesnt show all pages, we only need to go through the shown ones
if (!PdfUtils.PageLayoutScrollingEnabled(PageLayoutMode))
{
switch (PdfUtils.HorizontalPagePosition(PageLayoutMode, PageNo))
{
case -1:
{
start = PageNo;
end = Math.Min(PageNo + 1, end); //because PageNo + 1 doesn't necessarily exist in this case
break;
}
case 0:
{
start = PageNo;
end = PageNo;
break;
}
case 1:
{
start = PageNo - 1; //pageNo-1 always exists in this case
end = PageNo;
break;
}
}
}
int changedPage = int.MaxValue;
PdfSourceRect oldCanvasRect = _canvasRect.Clone();
bool entireCanvasDirty = (canvasDirty == TCanvasDirtyness.CanvasDirty);
canvasDirty = TCanvasDirtyness.Clean;
if (entireCanvasDirty)
{
_canvasRect.dWidth = 0.0;
_canvasRect.dX = 0.0;
}
double offset = 0.0;
int page = entireCanvasDirty ? start : Math.Max(start, GetNextRelevantPage(start, end));
for (; page <= end; page++)
{
PdfSourceRect rect = null;
if (pagesToLoadExactly.Remove(page))
{
Logger.LogInfo("page " + page + " was loaded exactly");
//load page exactly
rect = documentManager.GetPageRect(page);
}
else
{
rect = documentManager.GetPageRectGuess(page);
}
int nPage;
lock (newlyLoadedPagesLock)
{
nPage = newlyLoadedPages.FirstOrDefault(number => number >= start && number <= end);
}
if (!entireCanvasDirty && nPage > 1 && nPage < page)
{
//maybe the getting of pages has getted a page before this one (due to predictionAlgorithm). In this case, consider this page first
page = nPage;
rect = documentManager.GetPageRectGuess(page);
}
bool removed = false;
lock (newlyLoadedPagesLock)
{
removed = newlyLoadedPages.Remove(page);
}
if (removed || entireCanvasDirty)//If the page is newly loaded, calculate its position exactly. Also if the entire canvas is dirty, calculate always
{
changedPage = Math.Min(changedPage, page);
//position the page newly, knowing that its the first time we know its exact size
switch (PdfUtils.HorizontalPagePosition(PageLayoutMode, page))
{
case 0:
{
//place 1 page
rect.dCenterX = 0.0;
rect.dY = GetPreviousBottom(page, start, end) + _borderSize;
if (rect.dX - _borderSize < _canvasRect.dX)
{
_canvasRect.dWidth += _canvasRect.dX - (rect.dX - _borderSize);
_canvasRect.dX = rect.dX - _borderSize;
}
if (rect.dRight + _borderSize > _canvasRect.dRight)
{
_canvasRect.dWidth += rect.dRight + _borderSize - _canvasRect.dRight;
}
offset = rect.dBottom + _borderSize - GetNextTop(page, start, end);
break;
}
case -1:
{
//place left page
rect.dRight = 0.0 - _borderSize / 2.0;
rect.dY = Math.Max(GetPreviousBottom(page, start, end), GetPreviousBottom(page - 1, start, end)) + _borderSize;
if (rect.dX - _borderSize < _canvasRect.dX)
{
_canvasRect.dWidth += _canvasRect.dX - (rect.dX - _borderSize);
_canvasRect.dX = rect.dX - _borderSize;
}
offset = rect.dY - GetNextTop(page, start, end);
break;
}
default:
{
//place right page
rect.dX = 0.0 + _borderSize / 2.0;
rect.dY = documentManager.GetPageRectGuess(page - 1).dY;
if (rect.dRight + _borderSize > _canvasRect.dRight)
{
_canvasRect.dWidth += rect.dRight + _borderSize - _canvasRect.dRight;
}
offset = Math.Max(GetPreviousBottom(page, start, end), rect.dBottom) + _borderSize - GetNextTop(page, start, end);
break;
}
}
}
else
{
//Only pages that are not newly loaded make it here. Adjust their offset
if (offset == 0.0)
{
//if there is no offset, we dont need to do anything until we hit a page that needs to be loaded anew
page = GetNextRelevantPage(start, end);
if (page == int.MaxValue)
{
break;//there is no more page to load -> stop iterating through pages
}
page--;
continue;
}
rect.Offset(0.0, offset);
}
}//end for-loop
//we have loaded and positioned all pages, now we only need to resize the canvas
lock (newlyLoadedPagesLock)
{
if (newlyLoadedPages.Count == 0 && pagesToLoadExactly.Count == 0)
{
canvasDirty = TCanvasDirtyness.Clean;
}
}
if (PdfUtils.HorizontalPagePosition(PageLayoutMode, end) == -1)
{
offset = documentManager.GetPageRectGuess(end).dBottom + _borderSize - _canvasRect.dBottom;
}
if (offset != 0.0)
{
_canvasRect.dHeight += offset;
CanvasRectChanged(oldCanvasRect, _canvasRect, changedPage);
}
return;
}
