Release v0.6.32: make screenshot pan test independent of viewport DPI

tests/screenshot_ui.cpp

@@ -225,6 +225,17 @@ int main(int argc, char **argv)
             require(c.zoom>zoom && std::abs(before.x-after.x)<=1 && std::abs(before.y-after.y)<=1,
                     "Ctrl+wheel zoom keeps image point under cursor");
             require(!c.history.canUndo(),"zoom does not add image edits to undo history");
+            // A fixed zoom can still fit inside a high-DPI editor. Size the
+            // fixture from the actual viewport, with room for the tested drag
+            // on both axes, then start from a centered view.
+            const double panZoom=std::max({1.0,
+                double(c.canvas.right-c.canvas.left+128)/(c.view.right-c.view.left),
+                double(c.canvas.bottom-c.canvas.top+128)/(c.view.bottom-c.view.top)});
+            ks::zoomCanvas(window,c,panZoom,center);
+            c.panX=c.panY=0; ks::layout(window,c);
+            require(c.view.left+15<c.canvas.left && c.view.top+10<c.canvas.top &&
+                    c.view.right>c.canvas.right && c.view.bottom>c.canvas.bottom,
+                    "pan fixture has drag clearance on both axes within the supported zoom range");
             auto view=c.view;
             SendMessageW(window,WM_MBUTTONDOWN,MK_MBUTTON,MAKELPARAM(center.x,center.y));
             SendMessageW(window,WM_MOUSEMOVE,MK_MBUTTON,MAKELPARAM(center.x+15,center.y+10));