[MSPAINT] Improve Zoom tool (#5798)

- Delete global zoomTo function.
- Add CCanvasWindow::zoomTo and
  CCanvasWindow::getNewZoomRect functions.
- Rename CCanvasWindow::updateScrollInfo as
  CCanvasWindow::updateScrollRange.
- Rename CCanvasWindow::resetScrollPos as
  CCanvasWindow::updateScrollPos.
- Draw the proper zoom rectangle on mouse move.
- Revert the active tool on click when the tool
  was Zoom.
CORE-19094

base/applications/mspaint/mouse.cpp

@@ -563,40 +563,67 @@ struct ColorTool : ToolBase
 // TOOL_ZOOM
 struct ZoomTool : ToolBase
 {
+    BOOL m_bZoomed = FALSE;
+
     ZoomTool() : ToolBase(TOOL_ZOOM)
     {
     }
 
+    BOOL getNewZoomRect(CRect& rcView, INT newZoom);
+
     void OnDrawOverlayOnCanvas(HDC hdc) override
     {
-        CRect rc;
-        canvasWindow.GetImageRect(rc);
-        canvasWindow.ImageToCanvas(rc);
-
-        POINT pt;
-        ::GetCursorPos(&pt);
-        ::ScreenToClient(canvasWindow, &pt);
-
-        // FIXME: Draw the border of the area that is to be zoomed in
-        if (rc.PtInRect(pt))
-            DrawXorRect(hdc, &rc);
+        CRect rcView;
+        INT oldZoom = toolsModel.GetZoom();
+        if (oldZoom < MAX_ZOOM && getNewZoomRect(rcView, oldZoom * 2))
+            DrawXorRect(hdc, &rcView);
     }
 
     void OnButtonDown(BOOL bLeftButton, LONG x, LONG y, BOOL bDoubleClick) override
     {
+        INT newZoom, oldZoom = toolsModel.GetZoom();
         if (bLeftButton)
-        {
-            if (toolsModel.GetZoom() < MAX_ZOOM)
-                zoomTo(toolsModel.GetZoom() * 2, x, y);
-        }
+            newZoom = (oldZoom < MAX_ZOOM) ? (oldZoom * 2) : MIN_ZOOM;
         else
+            newZoom = (oldZoom > MIN_ZOOM) ? (oldZoom / 2) : MAX_ZOOM;
+
+        m_bZoomed = FALSE;
+
+        if (oldZoom != newZoom)
         {
-            if (toolsModel.GetZoom() > MIN_ZOOM)
-                zoomTo(toolsModel.GetZoom() / 2, x, y);
+            CRect rcView;
+            if (getNewZoomRect(rcView, newZoom))
+            {
+                canvasWindow.zoomTo(newZoom, rcView.left, rcView.top);
+                m_bZoomed = TRUE;
+            }
         }
     }
+
+    BOOL OnButtonUp(BOOL bLeftButton, LONG& x, LONG& y) override
+    {
+        if (m_bZoomed)
+            toolsModel.SetActiveTool(toolsModel.GetOldActiveTool());
+
+        return TRUE;
+    }
 };
 
+BOOL ZoomTool::getNewZoomRect(CRect& rcView, INT newZoom)
+{
+    CPoint pt;
+    ::GetCursorPos(&pt);
+    canvasWindow.ScreenToClient(&pt);
+
+    canvasWindow.getNewZoomRect(rcView, newZoom, pt);
+
+    CRect rc;
+    canvasWindow.GetImageRect(rc);
+    canvasWindow.ImageToCanvas(rc);
+
+    return rc.PtInRect(pt);
+}
+
 // TOOL_PEN
 struct PenTool : SmoothDrawTool
 {