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(svn r11456) -Fix [FS#1412] (r10070): Viewport is bound to its top-left corner

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smatz 2007-11-18 13:13:59 +00:00
parent 3c020cfd68
commit d749fda9e4
2 changed files with 47 additions and 4 deletions
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11
src/viewport.cpp
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@ -296,10 +296,13 @@ static void SetViewportPosition(Window *w, int x, int y)
vp->virtual_left = x;
vp->virtual_top = y;
old_left = UnScaleByZoom(old_left, vp->zoom);
old_top = UnScaleByZoom(old_top, vp->zoom);
x = UnScaleByZoom(x, vp->zoom);
y = UnScaleByZoom(y, vp->zoom);
/* viewport is bound to its left top corner, so it must be rounded down (UnScaleByZoomLower)
* else glitch described in FS#1412 will happen (offset by 1 pixel with zoom level > NORMAL)
*/
old_left = UnScaleByZoomLower(old_left, vp->zoom);
old_top = UnScaleByZoomLower(old_top, vp->zoom);
x = UnScaleByZoomLower(x, vp->zoom);
y = UnScaleByZoomLower(y, vp->zoom);
old_left -= x;
old_top -= y;

40
src/zoom.hpp
View File

@ -32,6 +32,13 @@ enum ZoomLevel {
extern ZoomLevel _saved_scrollpos_zoom;
/**
* Scale by zoom level, usually shift left (when zoom > ZOOM_LVL_NORMAL)
* When shifting right, value is rounded up
* @param value value to shift
* @param zoom zoom level to shift to
* @return shifted value
*/
static inline int ScaleByZoom(int value, ZoomLevel zoom)
{
if (zoom == ZOOM_LVL_NORMAL) return value;
@ -39,6 +46,13 @@ static inline int ScaleByZoom(int value, ZoomLevel zoom)
return (zoom > ZOOM_LVL_NORMAL) ? value << izoom : (value + (1 << -izoom) - 1) >> -izoom;
}
/**
* Scale by zoom level, usually shift right (when zoom > ZOOM_LVL_NORMAL)
* When shifting right, value is rounded up
* @param value value to shift
* @param zoom zoom level to shift to
* @return shifted value
*/
static inline int UnScaleByZoom(int value, ZoomLevel zoom)
{
if (zoom == ZOOM_LVL_NORMAL) return value;
@ -46,4 +60,30 @@ static inline int UnScaleByZoom(int value, ZoomLevel zoom)
return (zoom > ZOOM_LVL_NORMAL) ? (value + (1 << izoom) - 1) >> izoom : value << -izoom;
}
/**
* Scale by zoom level, usually shift left (when zoom > ZOOM_LVL_NORMAL)
* @param value value to shift
* @param zoom zoom level to shift to
* @return shifted value
*/
static inline int ScaleByZoomLower(int value, ZoomLevel zoom)
{
if (zoom == ZOOM_LVL_NORMAL) return value;
int izoom = (int)zoom - (int)ZOOM_LVL_NORMAL;
return (zoom > ZOOM_LVL_NORMAL) ? value << izoom : value >> -izoom;
}
/**
* Scale by zoom level, usually shift right (when zoom > ZOOM_LVL_NORMAL)
* @param value value to shift
* @param zoom zoom level to shift to
* @return shifted value
*/
static inline int UnScaleByZoomLower(int value, ZoomLevel zoom)
{
if (zoom == ZOOM_LVL_NORMAL) return value;
int izoom = (int)zoom - (int)ZOOM_LVL_NORMAL;
return (zoom > ZOOM_LVL_NORMAL) ? value >> izoom : value << -izoom;
}
#endif /* ZOOM_HPP */