[QgsQuick] - externalResource widget handler (#9232)

* [QgsQuick] - extended externalResource widget

Added removeFile function and modified fileName function - former has been missing and photoPanel is using it. The latter needed modification due to a new option to choose image from a gallery.
Added externalResource handler for externalResource widget which enables following features:
* option to choose an image from a gallery - selected image is copied to projects folder, if it doesnt exists there. Added "ic_gallery" icon.
* ability to remove value for externalResource field. Optionally removes referenced image as well ("Ok" option in dialog)
* ability to interact with image preview onClick - the main idea is to have ability to enlarge preview image. Currently its possible only in edit state of the form since the whole field is disabled otherwise.

Fixed resizing of icon/previewImage and component itself as well.

* [QgsQuick] - extended externalResource widget
Commit contains following fixes/changes/additions after review:
* Added QgsQuickUtils::getRelativePath which replaced QgsQuickUtils::getFileName + related changes in photoPanel
* Added test for new QgsQuickUtils functionality
* fixed weird or redundant size definitions in externalResource widget
* Some changes in docs.

* [QgsQuick] Changed "default" case result for QgsQuickUtils::getRelativePath

* [QgsQuick] Fixed test after changed functionality in QgsQuickUtils

src/quickgui/images/images.qrc

@@ -10,5 +10,6 @@
         <file>ic_photo_notavailable_white.svg</file>
         <file>ic_save_white.svg</file>
         <file>ic_camera.svg</file>
+        <file>ic_gallery.svg</file>
     </qresource>
 </RCC>

src/quickgui/plugin/editor/qgsquickexternalresource.qml

@@ -31,13 +31,13 @@ Item {
   property var notavailableImageSource: QgsQuick.Utils.getThemeIcon("ic_photo_notavailable_white")
 
   id: fieldItem
+  height: image.hasValidSource? customStyle.height * 3 : customStyle.height
   anchors {
     left: parent.left
     right: parent.right
     rightMargin: 10 * QgsQuick.Utils.dp
   }
 
-  height: Math.max(image.height, button.height)
   QgsQuick.PhotoCapture {
     id: photoCapturePanel
     visible: false
@@ -52,11 +52,21 @@ Item {
     property bool hasValidSource: false
 
     id: image
-    height: hasValidSource? customStyle.height * 3 : customStyle.height
+    height: fieldItem.height
+    sourceSize.height: height
     autoTransform: true
     fillMode: Image.PreserveAspectFit
     visible: hasValidSource
 
+    MouseArea {
+        anchors.fill: parent
+        onClicked: externalResourceHandler.previewImage(homePath + "/" + image.currentValue)
+    }
+
+    onCurrentValueChanged: {
+        image.source = image.getSource()
+    }
+
     onSourceChanged: {
         hasValidSource = (image.source ===  fieldItem.brokenImageSource ||
                           image.source === fieldItem.notavailableImageSource) ? false : true
@@ -81,6 +91,66 @@ Item {
       visible: !image.hasValidSource
   }
 
+  Button {
+    id: deleteButton
+    visible: fieldItem.enabled && image.hasValidSource
+    width: customStyle.height
+    height: width
+    padding: 0
+
+    anchors.right: imageBrowserButton.left
+    anchors.bottom: parent.bottom
+    anchors.verticalCenter: parent.verticalCenter
+
+    onClicked: externalResourceHandler.removeImage(fieldItem, homePath + "/" + image.currentValue)
+
+    background: Image {
+      id: deleteIcon
+      source: QgsQuick.Utils.getThemeIcon("ic_delete_forever_white")
+      width: deleteButton.width
+      height: deleteButton.height
+      sourceSize.width: width
+      sourceSize.height: height
+      fillMode: Image.PreserveAspectFit
+    }
+
+    ColorOverlay {
+        anchors.fill: deleteIcon
+        source: deleteIcon
+        color: customStyle.fontColor
+    }
+  }
+
+  Button {
+    id: imageBrowserButton
+    visible: fieldItem.enabled
+    width: customStyle.height
+    height: width
+    padding: 0
+
+    anchors.right: button.left
+    anchors.bottom: parent.bottom
+    anchors.verticalCenter: parent.verticalCenter
+
+    onClicked:externalResourceHandler.chooseImage(fieldItem)
+
+    background: Image {
+      id: browseIcon
+      source: QgsQuick.Utils.getThemeIcon("ic_gallery")
+      width: imageBrowserButton.width
+      height: imageBrowserButton.height
+      sourceSize.width: width
+      sourceSize.height: height
+      fillMode: Image.PreserveAspectFit
+    }
+
+    ColorOverlay {
+        anchors.fill: browseIcon
+        source: browseIcon
+        color: customStyle.fontColor
+    }
+  }
+
   Button {
     id: button
     visible: fieldItem.enabled

src/quickgui/plugin/qgsquickfeatureform.qml

@@ -36,6 +36,34 @@ Item {
    */
   signal canceled
 
+   /**
+    * A handler for extra events in externalSourceWidget.
+    */
+  property var externalResourceHandler: QtObject {
+
+        /**
+         * Called when clicked on the gallery icon to choose a file in a gallery.
+         * \param itemWidget editorWidget for modified field to send valueChanged signal.
+         */
+        property var chooseImage: function chooseImage(itemWidget) {
+        }
+
+        /**
+          * Called when clicked on the photo image. Suppose to be used to bring a bigger preview.
+          * \param imagePath Absolute path to the image.
+          */
+        property var previewImage: function previewImage(imagePath) {
+        }
+
+        /**
+          * Called when clicked on the trash icon. Suppose to delete the value and optionally also the image.
+          * \param itemWidget editorWidget for modified field to send valueChanged signal.
+          * \param imagePath Absolute path to the image.
+          */
+        property var removeImage: function removeImage(itemWidget, imagePath) {
+        }
+    }
+
   /**
    * AttributeFormModel binded on a feature supporting auto-generated editor layouts and "tab" layout.
    */
@@ -320,6 +348,7 @@ Item {
           property var constraintValid: ConstraintValid
           property var homePath: form.project ? form.project.homePath : ""
           property var customStyle: form.style.fields
+          property var externalResourceHandler: form.externalResourceHandler
 
           active: widget !== 'Hidden'
 

src/quickgui/plugin/qgsquickphotopanel.qml

@@ -73,7 +73,7 @@ Drawer {
     Component.onDestruction: {
       if (!captureItem && camera.imageCapture.capturedImagePath != ""){
         captureItem.saveImage = false
-        QgsQuick.Utils.remove(camera.imageCapture.capturedImagePath)
+        QgsQuick.Utils.removeFile(camera.imageCapture.capturedImagePath)
       }
       captureItem.saveImage = false
     }
@@ -164,7 +164,7 @@ Drawer {
               captureItem.saveImage = false
               photoPreview.visible = false
               if (camera.imageCapture.capturedImagePath != "") {
-                QgsQuick.Utils.remove(camera.imageCapture.capturedImagePath)
+                QgsQuick.Utils.removeFile(camera.imageCapture.capturedImagePath)
               }
             }
           }
@@ -200,7 +200,7 @@ Drawer {
             onClicked: {
               captureItem.saveImage = true
               photoPanel.visible = false
-              photoPanel.lastPhotoName = QgsQuick.Utils.getFileName(camera.imageCapture.capturedImagePath)
+              photoPanel.lastPhotoName = QgsQuick.Utils.getRelativePath(camera.imageCapture.capturedImagePath, photoPanel.targetDir)
               if (photoPanel.lastPhotoName !== "") {
                 fieldItem.image.source = photoPanel.targetDir + "/" + photoPanel.lastPhotoName
                 fieldItem.valueChanged(photoPanel.lastPhotoName, photoPanel.lastPhotoName === "" || photoPanel.lastPhotoName === null)

src/quickgui/qgsquickutils.cpp

@@ -95,11 +95,22 @@ bool QgsQuickUtils::fileExists( const QString &path )
   return ( check_file.exists() && check_file.isFile() );
 }
 
-QString QgsQuickUtils::getFileName( const QString &path )
+QString QgsQuickUtils::getRelativePath( const QString &path, const QString &prefixPath )
 {
-  QFileInfo fileInfo( path );
-  QString filename( fileInfo.fileName() );
-  return filename;
+  QString resultPath = path;
+  QString prefixPathWithSlash;
+  if ( !prefixPath.endsWith( "/" ) )
+    prefixPathWithSlash = QStringLiteral( "%1/" ).arg( prefixPath );
+  else
+    prefixPathWithSlash = prefixPath;
+
+  if ( resultPath.startsWith( prefixPathWithSlash ) )
+    return resultPath.replace( prefixPathWithSlash, QString() );
+  QString filePrefixPath = QStringLiteral( "file://%1" ).arg( prefixPathWithSlash );
+  if ( resultPath.startsWith( filePrefixPath ) )
+    return resultPath.replace( filePrefixPath, QString() );
+
+  return QString();
 }
 
 void QgsQuickUtils::logMessage( const QString &message, const QString &tag, Qgis::MessageLevel level )
@@ -162,6 +173,12 @@ QString QgsQuickUtils::formatDistance( double distance,
          .arg( QgsUnitTypes::toAbbreviatedString( destUnits ) );
 }
 
+bool QgsQuickUtils::removeFile( const QString &filePath )
+{
+  QFile file( filePath );
+  return file.remove( filePath );
+}
+
 
 void QgsQuickUtils::humanReadableDistance( double srcDistance, QgsUnitTypes::DistanceUnit srcUnits,
     QgsUnitTypes::SystemOfMeasurement destSystem,

src/quickgui/qgsquickutils.h

@@ -124,10 +124,13 @@ class QUICK_EXPORT QgsQuickUtils: public QObject
     Q_INVOKABLE static bool fileExists( const QString &path );
 
     /**
-     * Extracts filename from path
-     * \since QGIS 3.4
+     * Returns relative path of the file to given prefixPath. If prefixPath does not match a path parameter,
+     * returns an empty string. If a path starts with "file://", this prefix is ignored.
+     * \param path Absolute path to file
+     * \param prefixPath
+     * \since QGIS 3.8
      */
-    Q_INVOKABLE static QString getFileName( const QString &path );
+    Q_INVOKABLE static QString getRelativePath( const QString &path, const QString &prefixPath );
 
     /**
       * Log message in QgsMessageLog
@@ -194,6 +197,16 @@ class QUICK_EXPORT QgsQuickUtils: public QObject
         int decimals,
         QgsUnitTypes::SystemOfMeasurement destSystem = QgsUnitTypes::MetricSystem );
 
+    /**
+      * Deletes file from a given path.
+      *
+      * \param filePath Absolute path to file
+      * \returns bool True, if removal was successful, otherwise false.
+      *
+      * \since QGIS 3.8
+      */
+    Q_INVOKABLE static bool removeFile( const QString &filePath );
+
     /**
       * Converts distance to human readable distance in destination system of measurement
       *

tests/src/quickgui/testqgsquickutils.cpp

@@ -43,6 +43,7 @@ class TestQgsQuickUtils: public QObject
     void loadIcon();
     void fileExists();
     void loadQmlComponent();
+    void getRelativePath();
 
   private:
     QgsQuickUtils utils;
@@ -144,7 +145,8 @@ void TestQgsQuickUtils::loadIcon()
   QUrl url = utils.getThemeIcon( "ic_save_white" );
   Q_ASSERT( url.toString() == QStringLiteral( "qrc:/ic_save_white.svg" ) );
 
-  QString fileName = utils.getFileName( url.toString() );
+  QFileInfo fileInfo( url.toString() );
+  QString fileName( fileInfo.fileName() );
   Q_ASSERT( fileName == QStringLiteral( "ic_save_white.svg" ) );
 }
 
@@ -164,5 +166,27 @@ void TestQgsQuickUtils::loadQmlComponent()
   Q_ASSERT( valuemap.path() == QString( "qgsquickvaluemap.qml" ) );
 }
 
+void TestQgsQuickUtils::getRelativePath()
+{
+  QString prefixPath = QStringLiteral( "%1/" ).arg( TEST_DATA_DIR );
+  QString fileName = QStringLiteral( "quickapp_project.qgs" );
+  QString path =  prefixPath + fileName;
+  QString relativePath = utils.getRelativePath( path, prefixPath );
+  QCOMPARE( fileName, relativePath );
+
+  QString fileName2 = QStringLiteral( "zip/test.zip" );
+  QString path2 = prefixPath + fileName2;
+  QString relativePath2 = utils.getRelativePath( path2, prefixPath );
+  QCOMPARE( fileName2, relativePath2 );
+
+  QString path3 = QStringLiteral( "file://" ) + path2;
+  QString relativePath3 = utils.getRelativePath( path3, prefixPath );
+  QCOMPARE( fileName2, relativePath3 );
+
+  QString relativePath4 = utils.getRelativePath( path2, QStringLiteral( "/dummy/path/" ) );
+  QCOMPARE( QString(), relativePath4 );
+}
+
+
 QGSTEST_MAIN( TestQgsQuickUtils )
 #include "testqgsquickutils.moc"