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Fix drawing cross hair on wxDC

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There is no need to draw cross hair lines within the entire viewport because only the part inside the current clipping region will be actually drawn. This way we can also avoid working with huge numeric values of coordinates (VIEWPORT_EXTENT = 2^27-1) which apparently are not handled properly by LineTo() API.

Closes #18526.
This commit is contained in:
Artur Wieczorek 2019-10-10 20:34:16 +02:00
parent 07e9b82925
commit bf4640f1d8
1 changed files with 10 additions and 8 deletions
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18
src/msw/dc.cpp
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@ -803,16 +803,18 @@ bool wxMSWDCImpl::DoGetPixel(wxCoord x, wxCoord y, wxColour *col) const
void wxMSWDCImpl::DoCrossHair(wxCoord x, wxCoord y) void wxMSWDCImpl::DoCrossHair(wxCoord x, wxCoord y)
{ {
wxCoord x1 = x-VIEWPORT_EXTENT; RECT rect;
wxCoord y1 = y-VIEWPORT_EXTENT; ::GetClipBox(GetHdc(), &rect);
wxCoord x2 = x+VIEWPORT_EXTENT; // Inflate the box by 1 unit in each direction
wxCoord y2 = y+VIEWPORT_EXTENT; // to compensate rounding errors if DC is the subject
// of complex transformation (is e.g. rotated).
::InflateRect(&rect, 1, 1);
wxDrawLine(GetHdc(), XLOG2DEV(x1), YLOG2DEV(y), XLOG2DEV(x2), YLOG2DEV(y)); wxDrawLine(GetHdc(), XLOG2DEV(rect.left), YLOG2DEV(y), XLOG2DEV(rect.right), YLOG2DEV(y));
wxDrawLine(GetHdc(), XLOG2DEV(x), YLOG2DEV(y1), XLOG2DEV(x), YLOG2DEV(y2)); wxDrawLine(GetHdc(), XLOG2DEV(x), XLOG2DEV(rect.top), XLOG2DEV(x), XLOG2DEV(rect.bottom));
CalcBoundingBox(x1, y1); CalcBoundingBox(rect.left, rect.top);
CalcBoundingBox(x2, y2); CalcBoundingBox(rect.right, rect.bottom);
} }
void wxMSWDCImpl::DoDrawLine(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2) void wxMSWDCImpl::DoDrawLine(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2)