[chronojump] webcam snapshot: if cannot change size, do it again without forcing it

[Xavier de Blas <xaviblas src gnome org>]

commit e4e86baf2dfb7b2e70ad3c3adf7ca2d954a12484
Author: Xavier de Blas <xaviblas gmail com>
Date:   Thu Nov 7 10:13:23 2019 +0100

    webcam snapshot: if cannot change size, do it again without forcing it

 src/webcam/webcamFfmpeg.cs | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)
---
diff --git a/src/webcam/webcamFfmpeg.cs b/src/webcam/webcamFfmpeg.cs
index 3e065dd1..478ce375 100644
--- a/src/webcam/webcamFfmpeg.cs
+++ b/src/webcam/webcamFfmpeg.cs
@@ -164,10 +164,18 @@ public class WebcamFfmpeg : Webcam
                if(os == UtilAll.OperatingSystems.MACOSX)
                        executable = System.IO.Path.Combine(Util.GetPrefixDir(), "bin/ffmpeg");
 
-               List<string> parameters = createParametersSnapshot();
+               List<string> parameters = createParametersSnapshot(true); //force size
 
                process = new Process();
                ExecuteProcess.Result execute_result = ExecuteProcess.run (executable, parameters, false, 
false);
+
+               //on a Windows tablet cannot change size on snapshot, so if snapshot is not successful, do it 
again wihout forcing size
+               if(os == UtilAll.OperatingSystems.WINDOWS && ! execute_result.success)
+               {
+                       parameters = createParametersSnapshot(false);
+                       execute_result = ExecuteProcess.run (executable, parameters, false, false);
+               }
+
                return execute_result.success;
        }
 
@@ -284,7 +292,7 @@ public class WebcamFfmpeg : Webcam
        }
 
        //ffmpeg -f v4l2 -s 400x400 -i /dev/video0 -ss 0:0:2 -frames 1 /tmp/out.jpg
-       private List<string> createParametersSnapshot()
+       private List<string> createParametersSnapshot(bool forceSize)
        {
                // ffplay /dev/video0
                List<string> parameters = new List<string>();
@@ -298,8 +306,11 @@ public class WebcamFfmpeg : Webcam
                else    //mac
                        parameters.Insert (i ++, "avfoundation");
 
-               parameters.Insert (i ++, "-s");
-               parameters.Insert (i ++, "400x400");
+               if(forceSize)
+               {
+                       parameters.Insert (i ++, "-s");
+                       parameters.Insert (i ++, "400x400");
+               }
 
                parameters.Insert (i ++, "-i");
                if(os == UtilAll.OperatingSystems.LINUX)