Merge lp:~ubuntu-sdk-team/ubuntu-ui-toolkit/dpr into lp:ubuntu-ui-toolkit

[Gerry Boland]

[RFC] Compensate for Qt's device pixel ratio multiplier

The UITK has flexible UI scaling support through the use of Grid Units, where one can set a grid unit to be an integer number of pixels, and the whole UI adopts to suit this. GRID_UNIT_PX=10 is the way to set this.

Qt however has its own scaling solution: QScreen::devicePixelRatio->qreal which is a multiplier applied internally to all sizing/positioning calculations. Only integer values are well supported, so 1,2,3... are the options, resulting in a x2, x3 scaling of the entire UI. For linux and X11, devicePixelRatio is specified with QT_DEVICE_PIXEL_RATIO=2. In this case, if a QML item is set to have height 100, it will be drawn 200 pixels high (but QML has no idea of this, it is still 100 in height)

This latter solution works for all Qt apps, whereas Grid units only apply to UITK-based apps. For a HighDPI desktop, we want to use both solutions.

However these two scaling solutions are cumulative. Should one set
QT_DEVICE_PIXEL_RATIO=2 GRID_UNIT_PX=10
then a box of height units.gu(1) will be drawn 20 physical pixels high.

The intention of this MR is to guarantee that GRID_UNIT_PX corresponds to physical pixels, no matter what QScreen::devicePixelRatio returns. To do this, it divides units.{gu,dp} by devicePixelRatio, so that when Qt multiplies it by devicePixelRatio again on draw, the desired physical pixel size is obtained.

To test, open the gallery with these 2 different envs:
QT_DEVICE_PIXEL_RATIO=1 GRID_UNIT_PX=10
QT_DEVICE_PIXEL_RATIO=2 GRID_UNIT_PX=10

Some visual inconsistencies are exact font rendering sizes and some rounding issues causing off-by-one positioning errors.

[lp:~ubuntu-sdk-team/ubuntu-ui-toolkit/dpr]

1172. By Gerry Boland on 2015-04-16

Cleanup debug output and re-enable tests

1173. By Gerry Boland on 2015-04-16

Remove translation changes in trunk to clean up diff with staging

1174. By Gerry Boland on 2015-04-20

UbuntuShape fixes for low GU values

1175. By Gerry Boland on 2015-04-20

More correct fix for UbuntuShape at different DPR, edges should render nicely now

1176. By Gerry Boland on 2015-04-21

Add tests to ensure units.gu and units.dp are being calculated correctly

1177. By Gerry Boland on 2015-04-24

No need to pass svg to scaling image provider for non-unit DPR. Expand on a comment explaining an odd line

1178. By Gerry Boland on 2015-04-27

Merge current staging branch

1179. By Gerry Boland on 2015-04-27

Revert 1173

1180. By Gerry Boland on 2015-04-28

Fix bad math

1181. By Gerry Boland on 2015-05-07

Merge staging

1182. By Gerry Boland on 2015-05-07

Update Ubuntu shape overlay for device pixel ratio too

1183. By Gerry Boland on 2015-05-19

In UbuntuShape, refactor DPR calculations to have radius in device pixels, simplifies updateGeometry

1184. By Gerry Boland on 2015-05-19

UCUnits - deconstify value params

1185. By Gerry Boland on 2015-05-19

Read device pixel ratio from QGuiApplication, instead of reading the env var

1186. By Gerry Boland on 2015-05-22

Rely on DPR from qGuiApp, do not read env var in UCUnits directly. Requires refactoring tests into separate binaries to be able to set that env var

1187. By Gerry Boland on 2015-05-22

Fix bug in SCI file rewriter for DPR>1

1188. By Gerry Boland on 2015-06-17

Merge trunk

1189. By Gerry Boland on 2015-06-17

Unnecessary copy of dpr value removed

1190. By Gerry Boland on 2015-06-17

[tests] added a custom minimal QPA plugin which includes device pixel support, to enable testing of dpr stuff

1191. By Gerry Boland on 2015-07-10

Merge trunk

1192. By Gerry Boland on 2015-07-10

Using custom QPA plugin, now have device pixel ratio unit tests passing

1193. By Gerry Boland on 2015-07-10

Add explanation text about DPR and GU

1194. By Gerry Boland on 2015-07-10

Consolidate the vocabulary a bit

1195. By Gerry Boland on 2015-07-10

Add missing build dependencies

1196. By Gerry Boland on 2015-07-14

Bump version

1197. By Gerry Boland on 2015-07-27

Merge staging and fix conflicts

1198. By Gerry Boland on 2015-07-27

Revert rev 1196

1199. By Gerry Boland on 2015-08-04

Merge staging, fix a conflict

1200. By Gerry Boland on 2015-08-11

Undo changes to paths for gallery launcher

1201. By Gerry Boland on 2015-08-11

Merge staging

1202. By Gerry Boland on 2015-08-12

Fix build fail - variable inited twice

1203. By Gerry Boland on 2015-08-12

Merge staging again

1204. By Gerry Boland on 2015-08-12

Merge staging again

1205. By Gerry Boland on 2015-08-12

Revert accidental changes to examples/ubuntu-ui-toolkit-gallery/po/nl.po

Unmerged revisions

=== modified file 'modules/Ubuntu/Components/plugin/ucqquickimageextension.cpp'
--- modules/Ubuntu/Components/plugin/ucqquickimageextension.cpp	2014-11-24 13:14:35 +0000
+++ modules/Ubuntu/Components/plugin/ucqquickimageextension.cpp	2015-04-16 11:47:11 +0000
@@ -78,13 +78,19 @@
     QString selectedFilePath = resolved.mid(separatorPosition+1);
 
     if (scaleFactor == "1") {
-        // No scaling. Just pass the file as is.
-        m_image->setSource(QUrl::fromLocalFile(selectedFilePath));
+        if (qFuzzyCompare(UCUnits::instance().devicePixelRatio(), 1.0f)) {
+            // No scaling. Just pass the file as is.
+            m_image->setSource(QUrl::fromLocalFile(selectedFilePath));
+        } else {
+            m_image->setSource(QUrl("image://scaling/1/" + selectedFilePath));
+            m_image->setSourceSize(m_image->sourceSize()); // explicitly set the source size as we know it
+        }
     } else {
         // Prepend "image://scaling" for the image to be loaded by UCScalingImageProvider.
-        if (!m_source.path().endsWith(".sci")) {
+        if (!m_source.path().endsWith(".sci")) { qDebug() << "scaled";
             // Regular image file
             m_image->setSource(QUrl("image://scaling/" + resolved));
+            m_image->setSourceSize(m_image->sourceSize()); // explicitly set the source size as we know it
         } else {
             // .sci image file. Rewrite the .sci file into a temporary file.
             bool rewritten = true;
@@ -111,6 +117,7 @@
             } else {
                 m_image->setSource(m_source);
             }
+            m_image->setSourceSize(m_image->sourceSize()); // explicitly set the source size as we know it
         }
     }
 }
 
=== modified file 'modules/Ubuntu/Components/plugin/ucubuntushape.cpp'
--- modules/Ubuntu/Components/plugin/ucubuntushape.cpp	2015-04-16 11:47:10 +0000
+++ modules/Ubuntu/Components/plugin/ucubuntushape.cpp	2015-04-16 11:47:11 +0000
@@ -320,10 +320,7 @@
     setFlag(ItemHasContents);
     QObject::connect(&UCUnits::instance(), SIGNAL(gridUnitChanged()), this,
                      SLOT(_q_gridUnitChanged()));
-    const float gridUnit = UCUnits::instance().gridUnit();
-    setImplicitWidth(implicitWidthGU * gridUnit);
-    setImplicitHeight(implicitHeightGU * gridUnit);
-    update();
+    _q_gridUnitChanged();
 }
 
 /*! \qmlproperty string UbuntuShape::radius
@@ -968,9 +965,9 @@
 
 void UCUbuntuShape::_q_gridUnitChanged()
 {
-    const float gridUnit = UCUnits::instance().gridUnit();
-    setImplicitWidth(implicitWidthGU * gridUnit);
-    setImplicitHeight(implicitHeightGU * gridUnit);
+    const float gridUnitInDevicePixels = UCUnits::instance().gridUnit() / UCUnits::instance().devicePixelRatio();
+    setImplicitWidth(implicitWidthGU * gridUnitInDevicePixels);
+    setImplicitHeight(implicitHeightGU * gridUnitInDevicePixels);
     update();
 }
 
@@ -1063,6 +1060,7 @@
 {
     Q_UNUSED(data);
 
+    const float dpr = UCUnits::instance().devicePixelRatio();
     const QSizeF itemSize(width(), height());
     if (itemSize.isEmpty()) {
         delete oldNode;
@@ -1101,12 +1099,12 @@
         }
         if (m_flags & DirtySourceTransform) {
             if (m_flags & SourceApiSet) {
-                updateSourceTransform(itemSize.width(), itemSize.height(), m_sourceFillMode,
+                updateSourceTransform(itemSize.width() * dpr, itemSize.height() * dpr, m_sourceFillMode,
                                       m_sourceHorizontalAlignment, m_sourceVerticalAlignment,
                                       sourceTexture->textureSize());
             } else {
                 FillMode imageFillMode = (m_flags & Stretched) ? Stretch : PreserveAspectCrop;
-                updateSourceTransform(itemSize.width(), itemSize.height(), imageFillMode,
+                updateSourceTransform(itemSize.width() * dpr, itemSize.height() * dpr, imageFillMode,
                                       m_imageHorizontalAlignment, m_imageVerticalAlignment,
                                       sourceTexture->textureSize());
             }
@@ -1133,7 +1131,7 @@
     // scaled down accordingly. The shape was using a fixed image for the corner before switching to
     // a distance field, since the corner wasn't taking the whole image (ending at ~80%) we need
     // to take that into account when the size is scaled down.
-    float radius = UCUnits::instance().gridUnit()
+    float radius = UCUnits::instance().gridUnit() / UCUnits::instance().devicePixelRatio()
         * (m_radius == Small ? smallRadiusGU : mediumRadiusGU);
     const float scaledDownRadius = qMin(itemSize.width(), itemSize.height()) * 0.5f * 0.8f;
     if (radius > scaledDownRadius) {
 
=== modified file 'modules/Ubuntu/Components/plugin/ucunits.cpp'
--- modules/Ubuntu/Components/plugin/ucunits.cpp	2015-03-03 13:47:48 +0000
+++ modules/Ubuntu/Components/plugin/ucunits.cpp	2015-04-16 11:47:11 +0000
@@ -24,6 +24,9 @@
 #include <QtCore/QDir>
 #include <QtCore/QRegularExpression>
 #include <QtCore/qmath.h>
+#include <QtCore/QDebug>
+#include <QtGui/QGuiApplication>
+#include <QtGui/QScreen>
 
 #define ENV_GRID_UNIT_PX "GRID_UNIT_PX"
 #define DEFAULT_GRID_UNIT_PX 8
@@ -65,7 +68,20 @@
 UCUnits::UCUnits(QObject *parent) :
     QObject(parent)
 {
-    m_gridUnit = getenvFloat(ENV_GRID_UNIT_PX, DEFAULT_GRID_UNIT_PX);
+    QScreen *screen = QGuiApplication::primaryScreen();
+    if (screen) {
+        m_devicePixelRatio = screen->devicePixelRatio();
+    } else {
+        m_devicePixelRatio = 1.0;
+    }
+
+    // If GRID_UNIT_PX set, always use it. If not, 1GU := DEFAULT_GRID_UNIT_PX * m_devicePixelRatio
+    if (qEnvironmentVariableIsSet(ENV_GRID_UNIT_PX)) {
+        m_gridUnit = getenvFloat(ENV_GRID_UNIT_PX, DEFAULT_GRID_UNIT_PX);
+    } else {
+        m_gridUnit = DEFAULT_GRID_UNIT_PX * m_devicePixelRatio;
+    }
+    qDebug() << "Initial GU" << m_gridUnit;
 }
 
 /*!
@@ -78,8 +94,8 @@
     return m_gridUnit;
 }
 
-void UCUnits::setGridUnit(float gridUnit)
-{
+void UCUnits::setGridUnit(const float gridUnit)
+{    qDebug() << "Override GU" << gridUnit;
     m_gridUnit = gridUnit;
     Q_EMIT gridUnitChanged();
 }
@@ -87,27 +103,35 @@
 /*!
     \qmlmethod real Units::dp(real value)
 
-    Returns the number of pixels \a value density independent pixels correspond to.
+    Returns the number of device pixels \a value density independent pixels correspond to.
 */
-float UCUnits::dp(float value)
+// Device pixels (and not actual pixels) because QML sizes in terms of device pixels.
+float UCUnits::dp(const float value)
 {
     const float ratio = m_gridUnit / DEFAULT_GRID_UNIT_PX;
     if (value <= 2.0) {
         // for values under 2dp, return only multiples of the value
-        return qRound(value * qFloor(ratio));
+        return qRound(value * qFloor(ratio)) / m_devicePixelRatio;
     } else {
-        return qRound(value * ratio);
+        return qRound(value * ratio) / m_devicePixelRatio;
     }
 }
 
 /*!
     \qmlmethod real Units::gu(real value)
 
-    Returns the number of pixels \a value grid units correspond to.
+    Returns the number of device pixels \a value grid units correspond to.
 */
-float UCUnits::gu(float value)
-{
-    return qRound(value * m_gridUnit);
+// Device pixels (and not actual pixels) because QML sizes in terms of device pixels.
+
+float UCUnits::gu(const float value)
+{
+    return qRound(value * m_gridUnit) / m_devicePixelRatio;
+}
+
+float UCUnits::devicePixelRatio() const
+{
+    return m_devicePixelRatio;
 }
 
 QString UCUnits::resolveResource(const QUrl& url)
@@ -172,11 +196,12 @@
 
         path = prefix + suffixForGridUnit(selectedGridUnitSuffix) + suffix;
         float scaleFactor = m_gridUnit / selectedGridUnitSuffix;
+        qDebug() << "P" << path << scaleFactor;
         return QString::number(scaleFactor) + "/" + path;
     }
 
     path = prefix + suffix;
-    if (QFile::exists(path)) {
+    if (QFile::exists(path)) { qDebug() << "P" << path;
         return QString("1") + "/" + path;
     }
 
 
=== modified file 'modules/Ubuntu/Components/plugin/ucunits.h'
--- modules/Ubuntu/Components/plugin/ucunits.h	2013-10-18 08:56:39 +0000
+++ modules/Ubuntu/Components/plugin/ucunits.h	2015-04-16 11:47:11 +0000
@@ -35,15 +35,16 @@
     }
 
     explicit UCUnits(QObject *parent = 0);
-    Q_INVOKABLE float dp(float value);
-    Q_INVOKABLE float gu(float value);
+    Q_INVOKABLE float dp(const float value);
+    Q_INVOKABLE float gu(const float value);
     QString resolveResource(const QUrl& url);
 
     // getters
     float gridUnit();
+    float devicePixelRatio() const;
 
     // setters
-    void setGridUnit(float gridUnit);
+    void setGridUnit(const float gridUnit);
 
 Q_SIGNALS:
     void gridUnitChanged();
@@ -53,6 +54,7 @@
     float gridUnitSuffixFromFileName(const QString &fileName);
 
 private:
+    float m_devicePixelRatio;
     float m_gridUnit;
 };
 
 
=== modified file 'ubuntu-sdk.pro'
--- ubuntu-sdk.pro	2015-03-12 14:13:58 +0000
+++ ubuntu-sdk.pro	2015-04-16 11:47:11 +0000
@@ -1,7 +1,7 @@
 include( documentation/documentation.pri )
 
 TEMPLATE = subdirs
-SUBDIRS += modules/ubuntu-ui-toolkit.pro tests examples po
+SUBDIRS += modules/ubuntu-ui-toolkit.pro #tests examples po
 
 BUILD_PATH_CONTENTS="SRC_DIR=\"$$PWD\"" \
                     "BUILD_DIR=\"$$OUT_PWD\""