From 74545848cb5d46518d58f79dc806d7c1ad7130be Mon Sep 17 00:00:00 2001
From: NathanW <woodrow.nathan@gmail.com>
Date: Wed, 13 Jul 2011 23:26:50 +1000
Subject: [PATCH] Added support to show help about selected function

---
 src/gui/qgsexpressionbuilder.cpp |  21 ++++--
 src/gui/qgsexpressionbuilder.h   |  15 ++++-
 src/ui/qgsexpressionbuilder.ui   | 106 +++++++++++++++++++++++++++++--
 3 files changed, 127 insertions(+), 15 deletions(-)

diff --git a/src/gui/qgsexpressionbuilder.cpp b/src/gui/qgsexpressionbuilder.cpp
index cd3c9d104440..f7514e89c73d 100644
--- a/src/gui/qgsexpressionbuilder.cpp
+++ b/src/gui/qgsexpressionbuilder.cpp
@@ -32,14 +32,17 @@ QgsExpressionBuilderWidget::QgsExpressionBuilderWidget(QgsVectorLayer *layer)
     this->registerItem("Operators","-"," -");
     this->registerItem("Operators","*"," * ");
     this->registerItem("Operators","/"," / ");
+    this->registerItem("Operators","^"," ^ ");
+    this->registerItem("Operators","="," = ");
+    this->registerItem("Operators","||"," || ","<b>|| (String Concatenation)</b> <br> Concats two values together into a string <br> <i>Usage:</i><br>'Dia' || Diameter");
 
-    this->registerItem("Geometry","Area"," $area ");
-    this->registerItem("Geometry","Length"," $length ");
+    this->registerItem("Geometry","Area"," $area ","<b>$area</b> <br> Returns the area the object. <br> Only applies to polygons.");
+    this->registerItem("Geometry","Length"," $length ","<b>$length</b> <br> Returns the length the object. <br> Only applies to polylines.");
     this->registerItem("Geometry","Perimeter"," $perimeter ");
     this->registerItem("Geometry","X"," $x ");
      this->registerItem("Geometry","Y"," $y ");
-     this->registerItem("Geometry","XAt"," xat() ");
-     this->registerItem("Geometry","YAt"," yat() ");
+     this->registerItem("Geometry","XAt"," xat( ");
+     this->registerItem("Geometry","YAt"," yat(  ");
 }
 
 QgsExpressionBuilderWidget::~QgsExpressionBuilderWidget()
@@ -72,8 +75,9 @@ void QgsExpressionBuilderWidget::on_expressionTree_clicked(const QModelIndex &in
    }
    else
    {
-       // We might be able to show help for the current selected item here.
+       // Show the help for the current item.
        mValueListWidget->clear();
+       txtHelpText->setText(item->getHelpText());
    }
 }
 
@@ -124,7 +128,12 @@ void QgsExpressionBuilderWidget::fillFieldValues(int fieldIndex, int countLimit)
 
 void QgsExpressionBuilderWidget::registerItem(QString group, QString label, QString expressionText)
 {
-    QgsExpressionItem* item = new QgsExpressionItem(label,expressionText);
+    this->registerItem(group,label,expressionText,"");
+}
+
+void QgsExpressionBuilderWidget::registerItem(QString group, QString label, QString expressionText, QString helpText)
+{
+    QgsExpressionItem* item = new QgsExpressionItem(label,expressionText, helpText);
     // Look up the group and insert the new function.
     if (mExpressionGroups.contains(group))
     {
diff --git a/src/gui/qgsexpressionbuilder.h b/src/gui/qgsexpressionbuilder.h
index f9c73cc1ce7a..b4127af81188 100644
--- a/src/gui/qgsexpressionbuilder.h
+++ b/src/gui/qgsexpressionbuilder.h
@@ -37,18 +37,26 @@
 class QgsExpressionItem : public QStandardItem
 {
     public:
-        QgsExpressionItem(QString label, QString expressionText)
+        QgsExpressionItem(QString label, QString expressionText, QString helpText)
             : QStandardItem(label)
         {
             mExpressionText = expressionText;
+            mHelpText = helpText;
         }
 
-        QString getExpressionText()
+        QgsExpressionItem(QString label, QString expressionText)
+            : QStandardItem(label)
         {
-            return mExpressionText;
+            mExpressionText = expressionText;
         }
+
+        QString getExpressionText() {   return mExpressionText;  }
+
+        QString getHelpText() {  return mHelpText;  }
+
     private:
         QString mExpressionText;
+        QString mHelpText;
 };
 
 class QgsExpressionBuilderWidget : public QWidget, private Ui::QgsExpressionBuilder {
@@ -62,6 +70,7 @@ class QgsExpressionBuilderWidget : public QWidget, private Ui::QgsExpressionBuil
     QString getExpressionString();
     void setExpressionString(const QString expressionString);
     void registerItem(QString group, QString label, QString expressionText);
+    void registerItem(QString group, QString label, QString expressionText, QString helpText);
 
 public slots:
     void on_mAllPushButton_clicked();
diff --git a/src/ui/qgsexpressionbuilder.ui b/src/ui/qgsexpressionbuilder.ui
index f875dfea7ea4..9f7917953211 100644
--- a/src/ui/qgsexpressionbuilder.ui
+++ b/src/ui/qgsexpressionbuilder.ui
@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>482</width>
-    <height>452</height>
+    <width>538</width>
+    <height>615</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -23,7 +23,16 @@
       <string>Operation List</string>
      </property>
      <layout class="QGridLayout" name="gridLayout_3">
-      <property name="margin">
+      <property name="leftMargin">
+       <number>2</number>
+      </property>
+      <property name="topMargin">
+       <number>4</number>
+      </property>
+      <property name="rightMargin">
+       <number>2</number>
+      </property>
+      <property name="bottomMargin">
        <number>2</number>
       </property>
       <property name="spacing">
@@ -55,7 +64,83 @@
        </widget>
       </item>
       <item row="0" column="1">
-       <widget class="QListWidget" name="mValueListWidget"/>
+       <layout class="QVBoxLayout" name="verticalLayout_2">
+        <property name="spacing">
+         <number>0</number>
+        </property>
+        <property name="topMargin">
+         <number>0</number>
+        </property>
+        <property name="rightMargin">
+         <number>0</number>
+        </property>
+        <item>
+         <widget class="QListWidget" name="mValueListWidget"/>
+        </item>
+        <item>
+         <widget class="QLabel" name="label">
+          <property name="text">
+           <string>Function Help</string>
+          </property>
+          <property name="textFormat">
+           <enum>Qt::AutoText</enum>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QScrollArea" name="scrollArea">
+          <property name="sizePolicy">
+           <sizepolicy hsizetype="Expanding" vsizetype="Maximum">
+            <horstretch>0</horstretch>
+            <verstretch>0</verstretch>
+           </sizepolicy>
+          </property>
+          <property name="maximumSize">
+           <size>
+            <width>16777215</width>
+            <height>300</height>
+           </size>
+          </property>
+          <property name="frameShape">
+           <enum>QFrame::NoFrame</enum>
+          </property>
+          <property name="widgetResizable">
+           <bool>true</bool>
+          </property>
+          <widget class="QWidget" name="scrollAreaWidgetContents">
+           <property name="geometry">
+            <rect>
+             <x>0</x>
+             <y>0</y>
+             <width>261</width>
+             <height>82</height>
+            </rect>
+           </property>
+           <layout class="QGridLayout" name="gridLayout_4">
+            <item row="0" column="0">
+             <widget class="QLabel" name="txtHelpText">
+              <property name="sizePolicy">
+               <sizepolicy hsizetype="Expanding" vsizetype="Expanding">
+                <horstretch>0</horstretch>
+                <verstretch>0</verstretch>
+               </sizepolicy>
+              </property>
+              <property name="text">
+               <string>fsbn</string>
+              </property>
+              <property name="alignment">
+               <set>Qt::AlignLeading|Qt::AlignLeft|Qt::AlignTop</set>
+              </property>
+              <property name="wordWrap">
+               <bool>true</bool>
+              </property>
+             </widget>
+            </item>
+           </layout>
+          </widget>
+         </widget>
+        </item>
+       </layout>
       </item>
      </layout>
     </widget>
@@ -108,7 +193,16 @@
       <property name="spacing">
        <number>2</number>
       </property>
-      <property name="margin">
+      <property name="leftMargin">
+       <number>0</number>
+      </property>
+      <property name="topMargin">
+       <number>4</number>
+      </property>
+      <property name="rightMargin">
+       <number>0</number>
+      </property>
+      <property name="bottomMargin">
        <number>0</number>
       </property>
       <item>
@@ -222,7 +316,7 @@
        <number>0</number>
       </property>
       <property name="topMargin">
-       <number>2</number>
+       <number>4</number>
       </property>
       <property name="rightMargin">
        <number>0</number>