[longomatch] Add new helper method to scale images

[Andoni Morales Alastruey <amorales src gnome org>]

commit 9d4e147a2466b31779953d5947c45ec20f3d1de2
Author: Andoni Morales Alastruey <ylatuya gmail com>
Date:   Tue May 27 18:40:18 2014 +0200

    Add new helper method to scale images

 LongoMatch.Core/Common/Image.cs |   22 ++++++++++++++++++----
 1 files changed, 18 insertions(+), 4 deletions(-)
---
diff --git a/LongoMatch.Core/Common/Image.cs b/LongoMatch.Core/Common/Image.cs
index 571fd44..658a87f 100644
--- a/LongoMatch.Core/Common/Image.cs
+++ b/LongoMatch.Core/Common/Image.cs
@@ -52,6 +52,18 @@ namespace LongoMatch.Common
                        Scale (Constants.MAX_THUMBNAIL_SIZE, Constants.MAX_THUMBNAIL_SIZE);
                }
                
+               public void ScaleFactor (int destWidth, int destHeight,
+                                        out double scaleX, out double scaleY,
+                                        out Point offset) {
+                       int oWidth = 0;
+                       int oHeight = 0;
+                       
+                       ComputeScale (Width, Height, destWidth, destHeight, out oWidth, out oHeight);
+                       scaleX = (double) oWidth / Width;
+                       scaleY = (double) oHeight / Height;
+                       offset = new Point ((destWidth - oWidth) / 2, (destHeight - oHeight) / 2);
+               }
+               
                // this constructor is automatically called during deserialization
                public Image (SerializationInfo info, StreamingContext context) {
                        try {
@@ -165,11 +177,13 @@ namespace LongoMatch.Common
 
                        if(inWidth > maxOutWidth || inHeight > maxOutHeight) {
                                double par = (double)inWidth /(double)inHeight;
+                               double outPar = (double)maxOutWidth /(double)maxOutHeight;
                                
-                               if(inHeight>inWidth)
-                                       outWidth = (int)(outHeight * par);
-                               else
-                                       outHeight = (int)(outWidth / par);
+                               if (outPar > par) {
+                                       outWidth = Math.Min (maxOutWidth, (int)(outHeight * par));
+                               } else {
+                                       outHeight = Math.Min (maxOutHeight, (int)(outWidth / par));
+                               }
                        }
                } 
        }