[composer] Support merged undo/redo commands for multiframe items

src/app/composer/qgscomposerhtmlwidget.cpp

@@ -200,7 +200,7 @@ void QgsComposerHtmlWidget::on_mMaxDistanceSpinBox_valueChanged( double val )
   if ( composition )
   {
     blockSignals( true );
-    composition->beginMultiFrameCommand( mHtml, tr( "Page break distance changed" ) );
+    composition->beginMultiFrameCommand( mHtml, tr( "Page break distance changed" ), QgsComposerMultiFrameMergeCommand::HtmlBreakDistance );
     mHtml->setMaxBreakDistance( val );
     composition->endMultiFrameCommand();
     blockSignals( false );
@@ -218,7 +218,7 @@ void QgsComposerHtmlWidget::htmlEditorChanged()
   if ( composition )
   {
     blockSignals( true );
-    composition->beginMultiFrameCommand( mHtml, tr( "HTML changed" ) );
+    composition->beginMultiFrameCommand( mHtml, tr( "HTML changed" ), QgsComposerMultiFrameMergeCommand::HtmlSource );
     mHtml->setHtml( mHtmlEditor->text() );
     composition->endMultiFrameCommand();
     blockSignals( false );
@@ -237,7 +237,7 @@ void QgsComposerHtmlWidget::stylesheetEditorChanged()
   if ( composition )
   {
     blockSignals( true );
-    composition->beginMultiFrameCommand( mHtml, tr( "User stylesheet changed" ) );
+    composition->beginMultiFrameCommand( mHtml, tr( "User stylesheet changed" ), QgsComposerMultiFrameMergeCommand::HtmlStylesheet );
     mHtml->setUserStylesheet( mStylesheetEditor->text() );
     composition->endMultiFrameCommand();
     blockSignals( false );

src/core/composer/qgscomposermultiframecommand.cpp

@@ -90,3 +90,27 @@ bool QgsComposerMultiFrameCommand::containsChange() const
 {
   return !( mPreviousState.isNull() || mAfterState.isNull() || mPreviousState.toString() == mAfterState.toString() );
 }
+
+
+QgsComposerMultiFrameMergeCommand::QgsComposerMultiFrameMergeCommand( QgsComposerMultiFrameMergeCommand::Context c, QgsComposerMultiFrame *multiFrame, const QString &text )
+    : QgsComposerMultiFrameCommand( multiFrame, text )
+    , mContext( c )
+{
+
+}
+
+QgsComposerMultiFrameMergeCommand::~QgsComposerMultiFrameMergeCommand()
+{
+
+}
+
+bool QgsComposerMultiFrameMergeCommand::mergeWith( const QUndoCommand *command )
+{
+  const QgsComposerMultiFrameCommand* c = dynamic_cast<const QgsComposerMultiFrameCommand*>( command );
+  if ( !c || mMultiFrame != c->multiFrame() )
+  {
+    return false;
+  }
+  mAfterState = c->afterState();
+  return true;
+}

src/core/composer/qgscomposermultiframecommand.h

@@ -35,10 +35,15 @@ class CORE_EXPORT QgsComposerMultiFrameCommand: public QUndoCommand
     void savePreviousState();
     void saveAfterState();
 
+    QDomDocument previousState() const { return mPreviousState.cloneNode().toDocument(); }
+    QDomDocument afterState() const { return mAfterState.cloneNode().toDocument(); }
+
     /**Returns true if previous state and after state are valid and different*/
     bool containsChange() const;
 
-  private:
+    const QgsComposerMultiFrame* multiFrame() const { return mMultiFrame; }
+
+  protected:
     QgsComposerMultiFrame* mMultiFrame;
 
     QDomDocument mPreviousState;
@@ -52,4 +57,29 @@ class CORE_EXPORT QgsComposerMultiFrameCommand: public QUndoCommand
     bool checkFirstRun();
 };
 
+/**A composer command that merges together with other commands having the same context (=id)
+ * for multi frame items. Keeps the oldest previous state and uses the newest after state.
+ * The purpose is to avoid too many micro changes in the history*/
+class CORE_EXPORT QgsComposerMultiFrameMergeCommand: public QgsComposerMultiFrameCommand
+{
+  public:
+    enum Context
+    {
+      Unknown = 0,
+      //composer html
+      HtmlSource,
+      HtmlStylesheet,
+      HtmlBreakDistance
+    };
+
+    QgsComposerMultiFrameMergeCommand( Context c, QgsComposerMultiFrame* multiFrame, const QString& text );
+    ~QgsComposerMultiFrameMergeCommand();
+
+    bool mergeWith( const QUndoCommand * command );
+    int id() const { return ( int )mContext; }
+
+  private:
+    Context mContext;
+};
+
 #endif // QGSCOMPOSERMULTIFRAMECOMMAND_H

src/core/composer/qgscomposition.cpp

@@ -2135,10 +2135,24 @@ void QgsComposition::cancelCommand()
   mActiveItemCommand = 0;
 }
 
-void QgsComposition::beginMultiFrameCommand( QgsComposerMultiFrame* multiFrame, const QString& text )
+void QgsComposition::beginMultiFrameCommand( QgsComposerMultiFrame* multiFrame, const QString& text, const QgsComposerMultiFrameMergeCommand::Context c )
 {
   delete mActiveMultiFrameCommand;
-  mActiveMultiFrameCommand = new QgsComposerMultiFrameCommand( multiFrame, text );
+
+  if ( !multiFrame )
+  {
+    mActiveMultiFrameCommand = 0;
+    return;
+  }
+
+  if ( c == QgsComposerMultiFrameMergeCommand::Unknown )
+  {
+    mActiveMultiFrameCommand = new QgsComposerMultiFrameCommand( multiFrame, text );
+  }
+  else
+  {
+    mActiveMultiFrameCommand = new QgsComposerMultiFrameMergeCommand( c, multiFrame, text );
+  }
   mActiveMultiFrameCommand->savePreviousState();
 }
 

src/core/composer/qgscomposition.h

@@ -30,6 +30,7 @@
 
 #include "qgsaddremoveitemcommand.h"
 #include "qgscomposeritemcommand.h"
+#include "qgscomposermultiframecommand.h"
 #include "qgsatlascomposition.h"
 #include "qgspaperitem.h"
 #include "qgscomposerobject.h"
@@ -430,7 +431,7 @@ class CORE_EXPORT QgsComposition : public QGraphicsScene
     /**Deletes current command*/
     void cancelCommand();
 
-    void beginMultiFrameCommand( QgsComposerMultiFrame* multiFrame, const QString& text );
+    void beginMultiFrameCommand( QgsComposerMultiFrame* multiFrame, const QString& text, const QgsComposerMultiFrameMergeCommand::Context c = QgsComposerMultiFrameMergeCommand::Unknown );
     void endMultiFrameCommand();
 
     /**Adds multiframe. The object is owned by QgsComposition until removeMultiFrame is called*/