Images viewer: zoom and scroll

diff --git a/src/be/nikiroo/fanfix_swing/gui/viewer/ViewerImages.java b/src/be/nikiroo/fanfix_swing/gui/viewer/ViewerImages.java
index 554c3504a9d43fa552acc1930ad6527affc15acc..04a9e764e4ca217bff812c3121b348969b803015 100644 (file)
--- a/src/be/nikiroo/fanfix_swing/gui/viewer/ViewerImages.java
+++ b/src/be/nikiroo/fanfix_swing/gui/viewer/ViewerImages.java
@@ -45,8 +45,8 @@ import be.nikiroo.fanfix_swing.images.IconGenerator.Size;
 import be.nikiroo.utils.Image;
 import be.nikiroo.utils.ui.DelayWorker;
 import be.nikiroo.utils.ui.ImageUtilsAwt;
-import be.nikiroo.utils.ui.NavBar;
 import be.nikiroo.utils.ui.ImageUtilsAwt.Rotation;
+import be.nikiroo.utils.ui.NavBar;
 import be.nikiroo.utils.ui.UIUtils;
 
 /**
@@ -112,6 +112,7 @@ public class ViewerImages extends JFrame {
 
        private double zoom = -1; // -1 = snap to width or height
        private double currentZoom = 1; // used to go from snap to + or -
+       private Dimension currentImageSize;
        private boolean zoomSnapWidth = true;
        private Rotation rotation = Rotation.NONE;
 
@@ -247,7 +248,7 @@ public class ViewerImages extends JFrame {
                                } else {
                                        newZoom = Math.round(newZoom * 100.0) / 100.0; // snap to 1%
                                }
-                               setZoom(newZoom, zoomSnapWidth);
+                               setZoom(newZoom, zoomSnapWidth, null);
                        }
                });
 
@@ -266,7 +267,7 @@ public class ViewerImages extends JFrame {
                                if (selected instanceof ZoomLevel) {
                                        ZoomLevel selectedZoomLevel = (ZoomLevel) selected;
                                        setZoom(selectedZoomLevel.zoom,
-                                                       selectedZoomLevel.zoomSnapWidth);
+                                                       selectedZoomLevel.zoomSnapWidth, null);
                                        return;
                                }
 
@@ -284,7 +285,7 @@ public class ViewerImages extends JFrame {
                                                throw new NumberFormatException("invalid");
                                        }
 
-                                       setZoom(pc / 100.0, newZoomSnapWidth);
+                                       setZoom(pc / 100.0, newZoomSnapWidth, null);
                                } catch (NumberFormatException nfe) {
                                }
                        }
@@ -305,7 +306,7 @@ public class ViewerImages extends JFrame {
                                } else {
                                        newZoom = Math.round(newZoom * 100.0) / 100.0; // snap to 1%
                                }
-                               setZoom(newZoom, zoomSnapWidth);
+                               setZoom(newZoom, zoomSnapWidth, null);
                        }
 
                });
@@ -334,7 +335,8 @@ public class ViewerImages extends JFrame {
                return sep;
        }
 
-       private void setZoom(double newZoom, boolean newZoomSnapWidth) {
+       private void setZoom(double newZoom, boolean newZoomSnapWidth,
+                       Point zoomCenterOffset) {
                if (newZoom > 0) {
                        zoomBoxModel.setSelectedItem(
                                        Integer.toString((int) Math.round(newZoom * 100)) + " %");
@@ -342,11 +344,16 @@ public class ViewerImages extends JFrame {
 
                zoom = newZoom;
                zoomSnapWidth = newZoomSnapWidth;
-               display(index, rotation, true);
+               display(index, rotation, false, zoomCenterOffset);
+       }
+
+       private synchronized void display(int index, Rotation rotation,
+                       boolean resetScroll) {
+               display(index, rotation, resetScroll, null);
        }
 
        private synchronized void display(int index, final Rotation rotation,
-                       final boolean resetScroll) {
+                       final boolean resetScroll, final Point zoomCenterOffset) {
                if (images.isEmpty()) {
                        return;
                }
@@ -364,6 +371,9 @@ public class ViewerImages extends JFrame {
 
                worker.delay("display:" + resetScroll,
                                new SwingWorker<ImageIcon, Void>() {
+                                       private double previousZoom;
+                                       private Rectangle scrollTo;
+
                                        @Override
                                        protected ImageIcon doInBackground() throws Exception {
                                                Rotation rotation = ViewerImages.this.rotation;
@@ -375,6 +385,12 @@ public class ViewerImages extends JFrame {
                                                BufferedImage resizedImage = ImageUtilsAwt.scaleImage(
                                                                areaSize, image, zoom, zoomSnapWidth);
 
+                                               Dimension previousImageSize = currentImageSize;
+                                               currentImageSize = new Dimension(
+                                                               resizedImage.getWidth(),
+                                                               resizedImage.getHeight());
+
+                                               previousZoom = currentZoom;
                                                if (!turn) {
                                                        currentZoom = (1.0 * resizedImage.getWidth())
                                                                        / image.getWidth();
@@ -383,6 +399,37 @@ public class ViewerImages extends JFrame {
                                                                        / image.getWidth();
                                                }
 
+                                               if (previousZoom != currentZoom
+                                                               && previousImageSize != null) {
+                                                       Rectangle view = scroll.getViewport().getViewRect();
+
+                                                       double ratioW = view.getCenterX()
+                                                                       / previousImageSize.width;
+                                                       double ratioH = view.getCenterY()
+                                                                       / previousImageSize.height;
+
+                                                       if (turn) {
+                                                               double tmp = ratioW;
+                                                               ratioW = ratioH;
+                                                               ratioH = tmp;
+                                                       }
+
+                                                       double centerX = ratioW * currentImageSize.width;
+                                                       double centerY = ratioH * currentImageSize.height;
+                                                       int x = (int) Math
+                                                                       .round(centerX - (view.width / 2.0));
+                                                       int y = (int) Math
+                                                                       .round(centerY - (view.height / 2.0));
+
+                                                       if (zoomCenterOffset != null) {
+                                                               x += zoomCenterOffset.x;
+                                                               y += zoomCenterOffset.y;
+                                                       }
+
+                                                       scrollTo = new Rectangle(x, y, //
+                                                                       view.width, view.height);
+                                               }
+
                                                return new ImageIcon(resizedImage);
                                        }
 
@@ -412,6 +459,8 @@ public class ViewerImages extends JFrame {
                                                        area.setIcon(img);
                                                        if (resetScroll) {
                                                                area.scrollRectToVisible(new Rectangle());
+                                                       } else if (scrollTo != null) {
+                                                               area.scrollRectToVisible(scrollTo);
                                                        }
                                                } catch (InterruptedException e) {
                                                        Instance.getInstance().getTraceHandler().error(e);
@@ -493,8 +542,13 @@ public class ViewerImages extends JFrame {
                        @Override
                        public void mouseWheelMoved(MouseWheelEvent e) {
                                if (e.isControlDown()) {
+                                       Rectangle view = new Rectangle(scroll.getLocationOnScreen(),
+                                                       scroll.getViewport().getViewRect().getSize());
+                                       int x = e.getLocationOnScreen().x - (int) view.getCenterX();
+                                       int y = e.getLocationOnScreen().y - (int) view.getCenterY();
+
                                        double diff = -0.1 * e.getWheelRotation();
-                                       setZoom(currentZoom + diff, zoomSnapWidth);
+                                       setZoom(currentZoom + diff, zoomSnapWidth, new Point(x, y));
                                        e.consume();
                                } else {
                                        wheeling.mouseWheelMoved(e);