Merge lp:~gcollura/ubuntu-calculator-app/reboot-better-scrolling-perf into lp:ubuntu-calculator-app

[Giulio Collura]

Improve scrolling performances by loading delegate items dynamically.

I've greatly improved scrolling performances, now rendering time is always around 10ms (see http://i.imgur.com/G7WqoGg.png). I've used a similar technique that music-app and ureadit are using.

[Bartosz Kosiorek (gang65)]

Works perfectly for me.

Thanks Giulio.

review: Approve

[Ubuntu Phone Apps Jenkins Bot (ubuntu-phone-apps-jenkins-bot)]

FAILED: Autolanding.
More details in the following jenkins job:
http://91.189.93.70:8080/job/ubuntu-calculator-app-reboot-autolanding/27/
Executed test runs:
    UNSTABLE: http://91.189.93.70:8080/job/generic-mediumtests-vivid/614
        deb: http://91.189.93.70:8080/job/generic-mediumtests-vivid/614/artifact/work/output/*zip*/output.zip
    SUCCESS: http://91.189.93.70:8080/job/ubuntu-calculator-app-reboot-vivid-amd64-autolanding/27

review: Needs Fixing (continuous-integration)

[Ubuntu Phone Apps Jenkins Bot (ubuntu-phone-apps-jenkins-bot)]

FAILED: Autolanding.
More details in the following jenkins job:
http://91.189.93.70:8080/job/ubuntu-calculator-app-reboot-autolanding/28/
Executed test runs:
    UNSTABLE: http://91.189.93.70:8080/job/generic-mediumtests-vivid/620
        deb: http://91.189.93.70:8080/job/generic-mediumtests-vivid/620/artifact/work/output/*zip*/output.zip
    SUCCESS: http://91.189.93.70:8080/job/ubuntu-calculator-app-reboot-vivid-amd64-autolanding/28

review: Needs Fixing (continuous-integration)

[Ubuntu Phone Apps Jenkins Bot (ubuntu-phone-apps-jenkins-bot)]

review: Approve (continuous-integration)

=== modified file 'app/ubuntu-calculator-app.qml'
--- app/ubuntu-calculator-app.qml	2015-01-06 22:10:04 +0000
+++ app/ubuntu-calculator-app.qml	2015-01-09 17:35:57 +0000
@@ -69,12 +69,20 @@
             StateChangeScript {
                 script: header.hide()
             }
+            PropertyChanges {
+                target: scrollableView
+                clip: false
+            }
         },
         State {
             name: "selection"
             StateChangeScript {
                 script: header.show()
             }
+            PropertyChanges {
+                target: scrollableView
+                clip: true
+            }
         }
     ]
 
@@ -234,30 +242,31 @@
         }
     }
 
-    MultipleSelectionVisualModel {
-        id: visualModel
-        model: calculationHistory.getContents()
-
-        onSelectionDone: {
-            for (var i = 0; i < items.count; i++) {
-                calculationHistory.deleteCalc(items.get(i).model.dbId, items.get(i).model.index);
-            }
-        }
-
-        delegate: Screen {
+    Component {
+        id: emptyDelegate
+        Item { }
+    }
+
+    Component {
+        id: screenDelegateComponent
+        Screen {
             id: screenDelegate
             width: parent ? parent.width : 0
 
+            property var model: itemModel
             visible: model.dbId != -1
 
             selectionMode: visualModel.isInSelectionMode
-            selected: visualModel.isSelected(screenDelegate)
+            selected: visualModel.isSelected(visualDelegate)
 
             property var removalAnimation
             function remove() {
                 removalAnimation.start();
             }
 
+            // parent is the loader component
+            property var visualDelegate: parent ? parent : null
+
             onSwippingChanged: {
                 visualModel.updateSwipeState(screenDelegate);
             }
@@ -268,22 +277,27 @@
 
             onItemClicked: {
                 if (visualModel.isInSelectionMode) {
-                    if (!visualModel.selectItem(screenDelegate)) {
-                        visualModel.deselectItem(screenDelegate);
+                    if (!visualModel.selectItem(visualDelegate)) {
+                        visualModel.deselectItem(visualDelegate);
                     }
                 }
             }
 
             onItemPressAndHold: {
                 visualModel.startSelection();
-                visualModel.selectItem(screenDelegate);
+                visualModel.selectItem(visualDelegate);
             }
 
-            leftSideAction: Action {
-                iconName: "delete"
-                text: i18n.tr("Delete")
-                onTriggered: {
-                    screenDelegate.remove();
+            leftSideAction: screenDelegateDeleteAction.item
+
+            Loader {
+                id: screenDelegateDeleteAction
+                sourceComponent: Action {
+                    iconName: "delete"
+                    text: i18n.tr("Delete")
+                    onTriggered: {
+                        screenDelegate.remove();
+                    }
                 }
             }
 
@@ -306,12 +320,42 @@
 
                 ScriptAction {
                     script: {
-                        calculationHistory.deleteCalc(dbId, index);
-                    }
-                }
-            }
-        }
-
+                        calculationHistory.deleteCalc(model.dbId, model.index);
+                    }
+                }
+            }
+        }
+    }
+
+    MultipleSelectionVisualModel {
+        id: visualModel
+        model: calculationHistory.getContents()
+
+        onSelectionDone: {
+            for (var i = 0; i < items.count; i++) {
+                calculationHistory.deleteCalc(items.get(i).model.dbId, items.get(i).model.index);
+            }
+        }
+
+        delegate: Component {
+            Loader {
+                property var itemModel: model
+                width: parent.width
+                height: model.dbId != -1 ? item.height : 0;
+                sourceComponent: screenDelegateComponent
+                opacity: ((y+height) >= scrollableView.contentY) && (y <= (scrollableView.contentY + scrollableView.height)) ? 1 : 0
+                onOpacityChanged: {
+                    if (this.hasOwnProperty('item') && this.item != null) {
+                        if (opacity > 0) {
+                            sourceComponent = screenDelegateComponent;
+                        } else {
+                            this.item.visible = false;
+                            sourceComponent = emptyDelegate;
+                        }
+                    }
+                }
+            }
+        }
     }
 
     ScrollableView {
@@ -323,7 +367,14 @@
         }
         id: scrollableView
         objectName: "scrollableView"
-        clip: true
+
+        Component.onCompleted: {
+            // FIXME: workaround for qtubuntu not returning values depending on the grid unit definition
+            // for Flickable.maximumFlickVelocity and Flickable.flickDeceleration
+            var scaleFactor = units.gridUnit / 8;
+            maximumFlickVelocity = maximumFlickVelocity * scaleFactor;
+            flickDeceleration = flickDeceleration * scaleFactor;
+        }
 
         Repeater {
             id: formulaView
@@ -371,8 +422,8 @@
             id: keyboardLoader
             width: parent.width
             source: mainView.width > mainView.height ? "ui/LandscapeKeyboard.qml" : "ui/PortraiKeyboard.qml"
+            opacity: ((y+height) >= scrollableView.contentY) && (y <= (scrollableView.contentY + scrollableView.height)) ? 1 : 0
         }
-
     }
 }
 

=== modified file 'app/upstreamcomponents/MultipleSelectionVisualModel.qml'
--- app/upstreamcomponents/MultipleSelectionVisualModel.qml	2015-01-05 10:34:35 +0000
+++ app/upstreamcomponents/MultipleSelectionVisualModel.qml	2015-01-09 17:35:57 +0000
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012-2013 Canonical, Ltd.
+ * Copyright (C) 2012-2015 Canonical, Ltd.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by

=== modified file 'debian/copyright'
--- debian/copyright	2015-01-05 12:19:09 +0000
+++ debian/copyright	2015-01-09 17:35:57 +0000
@@ -7,6 +7,7 @@
            2014 Bartosz Kosiorek <[e-mail]>
            2014 Michael Zanetti <[e-mail]>
            2014-2015 Riccardo Padovani <[e-mail]>
+           2015 Giulio Collura <[e-mail]>
 License: GPL-3
 
 Files: debian/*