Added the ability to pan chart images.

src/MainForm.cs

@@ -1,5 +1,6 @@
 using System ;
 using System.IO ;
+using System.Drawing ;
 using System.Collections.Generic ;
 using System.Windows.Forms ;
 
@@ -19,7 +20,11 @@ public partial class MainForm : Form
     private Label mSearchLabel = new Label() ;
     private TextBox mSearchQuery = new TextBox() ;
     private ImageListView mSearchResults = new ImageListView() ;
-    private PictureBox mImagePictureBox = new PictureBox() ;
+    private Panel mChartImagePanel = new Panel() ;
+    private PictureBox mChartImagePictureBox = new PictureBox() ;
+
+    private Point? mMouseDragAnchor = null ;
+    private Tuple<int,int> mScrollDragAnchor ;
 
     public MainForm()
     {

src/MainForm.ui.cs

@@ -52,7 +52,7 @@ public partial class MainForm : Form
         this.mSearchResults.SetRenderer( new AppImageListView.AppImageListViewRenderer() ) ;
         this.mSearchResults.CacheMode = CacheMode.Continuous ;
         this.mSearchResults.Location = new Point( mSearchUserControl.Location.X + mSearchUserControl.Width, margin ) ;
-        Size searchResultsSize = new Size( mSplitter.Width - (mSearchQuery.Location.X + mSearchQuery.Width) - margin, mSplitter.Panel1MinSize ) ;
+        Size searchResultsSize = new Size( mSplitter.Width - (mSearchQuery.Location.X + mSearchQuery.Width) - margin - 7, mSplitter.Panel1MinSize ) ;
         this.mSearchResults.Size = searchResultsSize ;
         this.mSearchResults.BorderStyle = BorderStyle.None ;
         this.mSearchResults.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom ;
@@ -61,25 +61,186 @@ public partial class MainForm : Form
 
         // initialize the bottom pane (image viewer)
         // FIXME! We will probably need something better to render the images, but this will do, for now...
-        this.mImagePictureBox.Dock = DockStyle.Fill ;
-        this.mImagePictureBox.SizeMode = PictureBoxSizeMode.Zoom ;
-        this.mSplitter.Panel2.Controls.Add( mImagePictureBox ) ;
+        this.mChartImagePictureBox.SizeMode = PictureBoxSizeMode.Zoom ;
+        // FUDGE! We need to put the PictureBox inside a Panel in order to get the h-scrollbar to appear :-/
+        mChartImagePanel.Anchor = AnchorStyles.Top | AnchorStyles.Left ;
+        mChartImagePanel.AutoScroll = true ;
+        mChartImagePanel.Controls.Add( mChartImagePictureBox ) ;
+        mSplitter.Panel2.Controls.Add( mChartImagePanel ) ;
 
         // initialize handlers
         this.Load += new EventHandler( this.MainForm_Load ) ;
+        this.Resize += new EventHandler( this.MainForm_Resize ) ;
         this.mSearchQuery.TextChanged += new EventHandler( this.SearchQuery_TextChanged ) ;
         this.mSearchQuery.KeyDown += new KeyEventHandler( this.SearchQuery_KeyDown ) ;
         this.mSearchResults.KeyPress += new KeyPressEventHandler( this.SearchResults_KeyPress ) ;
         this.mSearchResults.SelectionChanged += new EventHandler( this.SearchResults_SelectionChanged ) ;
+
+        mChartImagePictureBox.MouseDown += new MouseEventHandler( this.ChartImagePictureBox_MouseDown ) ;
+        mChartImagePictureBox.MouseMove += new MouseEventHandler( this.ChartImagePictureBox_MouseMove ) ;
+        mChartImagePictureBox.MouseUp += new MouseEventHandler( this.ChartImagePictureBox_MouseUp ) ;
+        // NOTE: We also register mouse event handlers for the panel, so that dragging will work if the user clicks
+        // inside the image panel, but not on the image itself (i.e. when the image is smaller than the panel).
+        mChartImagePanel.MouseDown += new MouseEventHandler( this.ChartImagePictureBox_MouseDown ) ;
+        mChartImagePanel.MouseMove += new MouseEventHandler( this.ChartImagePictureBox_MouseMove ) ;
+        mChartImagePanel.MouseUp += new MouseEventHandler( this.ChartImagePictureBox_MouseUp ) ;
+    }
+
+    public bool preFilterMessage( ref Message msg )
+    {
+        // FUDGE! On Windows, when we handle Ctrl/Shift-ScrollWheel, Windows still wants to scroll the ChartImage.
+        // To stop this, we disable mouse wheel messages and handle everything ourself :-/
+        if ( msg.Msg == 0x020A ) { // nb: WM_MOUSEWHEEL
+            ulong wParam = (ulong)msg.WParam & 0xFFFFFFFF ;
+            int nLines = (int)( wParam >> 16 ) ;
+            if ( (nLines & 0x8000) != 0 )
+                nLines = nLines - 0x10000 ; // nb: negate the 32-bit value
+            nLines = nLines * SystemInformation.MouseWheelScrollLines / 120 ;
+            if ( (wParam & 0xFFFF) == 0 )
+                nLines = - nLines ; // nb: no virtual keys are down
+            this.scrollMainForm( nLines ) ;
+            return true ;
+        }
+        return false ;
     }
 
     private void MainForm_Load( object sender, EventArgs e )
     {
+        // initialize
+        MainForm_Resize( this, null ) ;
+
         // load the chart images
         loadChartImages() ;
         loadSearchResults( mChartImages.Values ) ;
     }
 
+    private void MainForm_Resize( object sender, EventArgs e )
+    {
+        // check if we are showing a ChartImage
+        Image img = mChartImagePictureBox.Image ;
+        if ( img == null ) {
+            mChartImagePanel.Visible = false ;
+            return ;
+        }
+        mChartImagePanel.Visible = true ;
+
+        // resize the ChartImage panel to fill the available space
+        mChartImagePanel.Size = new Size(
+            mSplitter.Panel2.Width - (Program.isMono?8:17),
+            mSplitter.Panel2.Height - (Program.isMono?28:40)
+        ) ;
+
+        // try to size the image to fill the available width
+        int margin = 5 ;
+        float aspectRatio = (float)img.Width / (float)img.Height ;
+        int availableWidth = mChartImagePanel.Width - 2*margin ;
+        int width = availableWidth ;
+        int height = (int) (availableWidth / aspectRatio) ;
+
+        // check that we're not zooming in/out too much
+        float zoom = (float)width / (float)img.Width ;
+        float minZoom = Program.appConfig.getFloatVal( new string[]{"MinZoom"}, 0.5f ) ;
+        float maxZoom = Program.appConfig.getFloatVal( new string[]{"MaxZoom"}, 2f ) ;
+        if ( minZoom > 0 && zoom < minZoom ) {
+            width = (int) (img.Width * minZoom) ;
+            height = (int) (img.Height * minZoom) ;
+        } else if ( maxZoom > 0 && zoom > maxZoom ) {
+            width = (int) (img.Width * maxZoom) ;
+            height = (int) (img.Height * maxZoom) ;
+        }
+
+        // check if the v-scrollbar is showing
+        if ( height >= mChartImagePanel.Height ) {
+            // yup - adjust the width
+            int sbWidth = SystemInformation.VerticalScrollBarWidth ;
+            availableWidth -= sbWidth ;
+            width -= sbWidth ;
+        }
+
+        // resize and position the ChartImage
+        // TODO: It would be nice to maintain the scroll position of the current image,
+        // but how .NET sets the scroll range/position is weird :-/
+        mChartImagePictureBox.Size = new Size( width, height ) ;
+        if ( width < availableWidth )
+            mChartImagePictureBox.Location = new Point( margin + (availableWidth - width)/2, margin ) ;
+        else
+            mChartImagePictureBox.Location = new Point( margin, margin ) ;
+        mChartImagePanel.HorizontalScroll.Value = 0 ;
+        mChartImagePanel.VerticalScroll.Value = 0 ;
+    }
+
+    private void ChartImagePictureBox_MouseDown( object sender, MouseEventArgs e )
+    {
+        // flag that the user has started to drag the ChartImage
+        // FUDGE! The mouse position as reported by the MouseEventArgs bounces around weirdly during mouse move,
+        // so we read the mouse position directly :shrug:
+        mMouseDragAnchor = Cursor.Position ;
+        mScrollDragAnchor = new Tuple<int,int>( mChartImagePanel.HorizontalScroll.Value, mChartImagePanel.VerticalScroll.Value ) ;
+        Cursor.Current = Cursors.Hand ;
+    }
+
+    private void ChartImagePictureBox_MouseMove( object sender, MouseEventArgs e )
+    {
+        // check if a drag is in progress
+        if ( mMouseDragAnchor == null )
+            return ;
+        Point pos = Cursor.Position ;
+        int deltaX = pos.X - mMouseDragAnchor.Value.X ;
+        int deltaY = pos.Y - mMouseDragAnchor.Value.Y ;
+        int scrollX = mScrollDragAnchor.Item1 - deltaX ;
+        int scrollY = mScrollDragAnchor.Item2 - deltaY ;
+        scrollChartImagePanel( scrollX, scrollY ) ;
+    }
+
+    private void ChartImagePictureBox_MouseUp( object sender, MouseEventArgs e )
+    {
+        // end the drag
+        mMouseDragAnchor = null ;
+        mScrollDragAnchor = null ;
+        Cursor.Current = Cursors.Default ;
+    }
+
+    private void scrollMainForm( int nLines )
+    {
+        // check if the mouse is over the ChartImage Panel
+        Point pos = Cursor.Position ;
+        pos = mChartImagePanel.PointToClient( pos ) ;
+        if ( pos.X < 0 || pos.X >= mChartImagePanel.Width || pos.Y < 0 || pos.Y >= mChartImagePanel.Height )
+            return ;
+        if ( (Control.ModifierKeys & Keys.Shift) != 0 ) {
+            // scroll the ChartImage left/right
+            HScrollProperties hscroll = mChartImagePanel.HorizontalScroll ;
+            int scrollRange = hscroll.Maximum - hscroll.Minimum ;
+            int scrollX = hscroll.Value + (int)( scrollRange * nLines/100 ) ;
+            scrollChartImagePanel( scrollX, null ) ;
+        } else {
+            // scroll the ChartImage up/down
+            VScrollProperties vscroll = mChartImagePanel.VerticalScroll ;
+            int scrollRange = vscroll.Maximum - vscroll.Minimum ;
+            int scrollY = vscroll.Value + (int)( scrollRange * nLines/100 ) ;
+            scrollChartImagePanel( null, scrollY ) ;
+        }
+    }
+
+    private void scrollChartImagePanel( int? scrollX, int? scrollY )
+    {
+        // update the scroll position
+        if ( scrollX != null ) {
+            HScrollProperties hscroll = mChartImagePanel.HorizontalScroll ;
+            int maxScrollX = hscroll.Maximum - mChartImagePanel.Width + 17 ;
+            int scrollPos = Math.Max( 0, Math.Min( maxScrollX, scrollX.Value ) ) ;
+            hscroll.Value = scrollPos ;
+            hscroll.Value = scrollPos ; // nb: for Windows :shrug:
+        }
+        if ( scrollY != null ) {
+            VScrollProperties vscroll = mChartImagePanel.VerticalScroll ;
+            int maxScrollY = vscroll.Maximum - mChartImagePanel.Height + 17 ;
+            int scrollPos = Math.Max( 0, Math.Min( maxScrollY, scrollY.Value ) ) ;
+            vscroll.Value = scrollPos ;
+            vscroll.Value = scrollPos ; // nb: for Windows :shrug:
+        }
+    }
+
     private void SearchResults_SelectionChanged( object sender, EventArgs e )
     {
         // show the selected chart image
@@ -87,9 +248,12 @@ public partial class MainForm : Form
         ChartImage chartImage ;
         if (  mSearchResults.SelectedItems.Count > 0 ) {
             chartImage = (ChartImage) mSearchResults.SelectedItems[0].Tag ;
-            mImagePictureBox.Image = chartImage.image ;
+            mChartImagePictureBox.Image = chartImage.image ;
         } else
-            mImagePictureBox.Image = null ;
+            mChartImagePictureBox.Image = null ;
+        mChartImagePanel.HorizontalScroll.Value = 0 ;
+        mChartImagePanel.VerticalScroll.Value = 0 ;
+        MainForm_Resize( this, null ) ;
     }
 
     private void SearchQuery_TextChanged( object sender, EventArgs e )

src/Program.cs

@@ -9,7 +9,12 @@ using log4net.Config ;
 
 public static class Program
 {
+    private class MyMessageFilter : IMessageFilter {
+        public bool PreFilterMessage( ref Message msg ) { return Program.preFilterMessage( ref msg ) ; }
+    }
+
     public const string APP_NAME = "ASL Charts" ;
+    private static bool mIsMono ;
 
     private static string mBaseDir ;
     private static string mDataDir ;
@@ -23,6 +28,7 @@ public static class Program
     {
         // initialize
         mBaseDir = Application.StartupPath ;
+        mIsMono = Type.GetType( "Mono.Runtime" ) != null ;
 
         // configure logging
         string fname = Path.Combine( mBaseDir, "log4net.xml" ) ;
@@ -62,6 +68,9 @@ public static class Program
             return ;
         }
 
+        // install our message filter
+        Application.AddMessageFilter( new MyMessageFilter() ) ;
+
         // run the application
         Application.EnableVisualStyles() ;
         Application.SetCompatibleTextRenderingDefault( false ) ;
@@ -69,10 +78,21 @@ public static class Program
         Application.Run( mMainForm ) ;
     }
 
+    public static bool preFilterMessage( ref Message msg )
+    {
+        // check if we should filter this message
+        if ( Program.mainForm.preFilterMessage( ref msg ) )
+            return true ;
+        return false ;
+    }
+
     public static void showInfoMsg( string msg ) { MessageBox.Show(msg,APP_NAME,MessageBoxButtons.OK,MessageBoxIcon.Information) ; }
     public static void showWarningMsg( string msg ) { MessageBox.Show(msg,APP_NAME,MessageBoxButtons.OK,MessageBoxIcon.Warning) ; }
     public static void showErrorMsg( string msg ) { MessageBox.Show(msg,APP_NAME,MessageBoxButtons.OK,MessageBoxIcon.Error) ; }
 
+    public static bool isMono { get { return mIsMono ; } }
+
+    public static MainForm mainForm { get { return mMainForm ; } }
     public static JsonConfig appConfig { get { return mAppConfig ; } }
     public static JsonConfig dataConfig { get { return mDataConfig ; } }
     public static JsonConfig debugConfig { get { return mDebugConfig ; } }