[freetype2-demos] master ec274ce 2/2: [ftinspect] Display grid.

[Werner LEMBERG]

branch: master
commit ec274ce9cd504f248a789927cff4d0661dcad28b
Author: Werner Lemberg <address@hidden>
Commit: Werner Lemberg <address@hidden>

    [ftinspect] Display grid.
    
    The dimensions are still arbitrary, though.
    
    We now need Qt 4.6 or newer.
    
    * src/ftinspect.h (Engine): Remove `zoom' member.  It doesn't belong
    here.
    (Grid): New class, derived from `QGraphicsItem'.  We need this to
    disable drawing of the grid if the zoom factor is too small.
    (MainGUI): Add a `QGraphicsScene' member.
    Add a `zoom' method.
    
    * src/ftinspect.cpp (Engine::update): Updated.
    (Grid::Grid, Grid::boundingRect, Grid::paint): New methods.
    (MainGUI::createLayout): Initialize `glyphView' and `glyphScene';
    add a grid object.
    Change zoomSpinBox to display an integer zoom factor instead of a
    percentage.  This simplifies code since we don't have to bother with
    scaling values < 1.
    (MainGUI::createConnections, MainGUI::setDefaults): Updated.
---
 ChangeLog         |   30 +++++++++++++++++--
 src/ftinspect.cpp |   83 +++++++++++++++++++++++++++++++++++++++++++++++++----
 src/ftinspect.h   |   19 +++++++++++-
 3 files changed, 122 insertions(+), 10 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index c3894e0..47653db 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,9 +1,33 @@
 2016-05-08  Werner Lemberg  <address@hidden>
 
-       [ftinspect] Provide some drawing colors.
+       [ftinspect] Display grid.
+
+       The dimensions are still arbitrary, though.
+
+       We now need Qt 4.6 or newer.
+
+       * src/ftinspect.h (Engine): Remove `zoom' member.  It doesn't belong
+       here.
+       (Grid): New class, derived from `QGraphicsItem'.  We need this to
+       disable drawing of the grid if the zoom factor is too small.
+       (MainGUI): Add a `QGraphicsScene' member.
+       Add a `zoom' method.
+
+       * src/ftinspect.cpp (Engine::update): Updated.
+       (Grid::Grid, Grid::boundingRect, Grid::paint): New methods.
+       (MainGUI::createLayout): Initialize `glyphView' and `glyphScene';
+       add a grid object.
+       Change zoomSpinBox to display an integer zoom factor instead of a
+       percentage.  This simplifies code since we don't have to bother with
+       scaling values < 1.
+       (MainGUI::createConnections, MainGUI::setDefaults): Updated.
+
+2016-05-08  Werner Lemberg  <address@hidden>
+
+       [ftinspect] Provide some drawing pens.
 
-       * src/ftinspect.h (MainGUI): Provide colors for axes, blue zones,
-       grid lines, on and off points, outlines, and segment lines.
+       * src/ftinspect.h (MainGUI): Provide colored pens for axes, blue
+       zones, grid lines, on and off points, outlines, and segment lines.
 
        * src/ftinspect.cpp (MainGUI::setGraphicsDefaults): New method.
        (MainGUI::MainGUI): Updated.
diff --git a/src/ftinspect.cpp b/src/ftinspect.cpp
index 2b219e9..91e4d82 100644
--- a/src/ftinspect.cpp
+++ b/src/ftinspect.cpp
@@ -346,7 +346,6 @@ void
 Engine::update()
 {
   dpi = gui->dpiSpinBox->value();
-  zoom = gui->zoomSpinBox->value();
 
   if (gui->unitsComboBox->currentIndex() == MainGUI::Units_px)
   {
@@ -447,6 +446,48 @@ Engine::update()
 }
 
 
+Grid::Grid(const QPen& p)
+: pen(p)
+{
+ // empty
+}
+
+
+QRectF
+Grid::boundingRect() const
+{
+  // XXX fix size
+
+  // no need to take care of pen width
+  return QRectF(0, 0,
+                100, 100);
+}
+
+
+void
+Grid::paint(QPainter* painter,
+            const QStyleOptionGraphicsItem* option,
+            QWidget*)
+{
+  const qreal lod = option->levelOfDetailFromTransform(
+                              painter->worldTransform());
+
+  painter->setPen(pen);
+
+  // don't draw grid if magnification is too small
+  if (lod >= 5)
+  {
+    // XXX fix size
+    for (qreal x = 0; x <= 100; x++ )
+      painter->drawLine(x, 0,
+                        x, 100);
+    for (qreal y = 0; y <= 100; y++)
+      painter->drawLine(0, y,
+                        100, y);
+  }
+}
+
+
 MainGUI::MainGUI()
 {
   setGraphicsDefaults();
@@ -970,6 +1011,24 @@ MainGUI::nextInstance()
 
 
 void
+MainGUI::zoom()
+{
+  int scale = zoomSpinBox->value();
+
+  QTransform transform;
+  transform.scale(scale, scale);
+
+  // we want horizontal and vertical 1px lines displayed with full pixels;
+  // we thus have to shift the coordinate system accordingly, using a value
+  // that represents 0.5px (i.e., half the 1px line width) after the scaling
+  qreal shift = 0.5 / scale;
+  transform.translate(shift, shift);
+
+  glyphView->setTransform(transform);
+}
+
+
+void
 MainGUI::setGraphicsDefaults()
 {
   // XXX make this user-configurable
@@ -1174,7 +1233,16 @@ MainGUI::createLayout()
   leftWidget->setSizePolicy(leftWidgetPolicy);
 
   // right side
+  glyphScene = new QGraphicsScene;
+  glyphScene->addItem(new Grid(gridPen));
+
   glyphView = new QGraphicsView;
+  glyphView->setRenderHint(QPainter::Antialiasing, true);
+  glyphView->setDragMode(QGraphicsView::ScrollHandDrag);
+  glyphView->setOptimizationFlags(QGraphicsView::DontSavePainterState);
+  glyphView->setViewportUpdateMode(QGraphicsView::SmartViewportUpdate);
+  glyphView->setTransformationAnchor(QGraphicsView::AnchorUnderMouse);
+  glyphView->setScene(glyphScene);
 
   sizeLabel = new QLabel(tr("Size "));
   sizeLabel->setAlignment(Qt::AlignRight);
@@ -1207,13 +1275,12 @@ MainGUI::createLayout()
   toP1000Buttonx = new QPushButtonx("+1000");
   toEndButtonx = new QPushButtonx(">|");
 
-  zoomLabel = new QLabel(tr("Zoom "));
+  zoomLabel = new QLabel(tr("Zoom Factor"));
   zoomLabel->setAlignment(Qt::AlignRight);
   zoomSpinBox = new QSpinBox;
   zoomSpinBox->setAlignment(Qt::AlignRight);
-  zoomSpinBox->setRange(1, 10000);
-  zoomSpinBox->setSuffix("%");
-  zoomSpinBox->setSingleStep(10);
+  zoomSpinBox->setRange(1, 1000);
+  zoomSpinBox->setSingleStep(1);
   zoomLabel->setBuddy(zoomSpinBox);
 
   previousFontButton = new QPushButton(tr("Previous Font"));
@@ -1308,6 +1375,9 @@ MainGUI::createConnections()
   connect(unitsComboBox, SIGNAL(currentIndexChanged(int)),
           SLOT(checkUnits()));
 
+  connect(zoomSpinBox, SIGNAL(valueChanged(int)),
+          SLOT(zoom()));
+
   connect(previousFontButton, SIGNAL(clicked()),
           SLOT(previousFont()));
   connect(nextFontButton, SIGNAL(clicked()),
@@ -1478,7 +1548,7 @@ MainGUI::setDefaults()
   gammaSlider->setValue(18); // 1.8
   sizeDoubleSpinBox->setValue(20);
   dpiSpinBox->setValue(96);
-  zoomSpinBox->setValue(100);
+  zoomSpinBox->setValue(20);
 
   checkHinting();
   checkHintingMode();
@@ -1490,6 +1560,7 @@ MainGUI::setDefaults()
   checkCurrentFontIndex();
   checkCurrentFaceIndex();
   checkCurrentInstanceIndex();
+  zoom();
 }
 
 
diff --git a/src/ftinspect.h b/src/ftinspect.h
index 8f14f6f..435aaeb 100644
--- a/src/ftinspect.h
+++ b/src/ftinspect.h
@@ -22,6 +22,8 @@
 #include <QDir>
 #include <QDoubleSpinBox>
 #include <QFileDialog>
+#include <QGraphicsItem>
+#include <QGraphicsScene>
 #include <QGraphicsView>
 #include <QGridLayout>
 #include <QHash>
@@ -43,6 +45,7 @@
 #include <QStandardItemModel>
 #include <QStatusBar>
 #include <QTabWidget>
+#include <QTransform>
 #include <QVariant>
 #include <QVBoxLayout>
 #include <QWidget>
@@ -130,7 +133,6 @@ private:
   double pointSize;
   double pixelSize;
   int dpi;
-  int zoom;
 
   bool doHinting;
   bool doAutoHinting;
@@ -151,6 +153,19 @@ private:
 };
 
 
+class Grid
+: public QGraphicsItem
+{
+public:
+  Grid(const QPen&);
+  QRectF boundingRect() const;
+  void paint(QPainter*, const QStyleOptionGraphicsItem*, QWidget*);
+
+private:
+  QPen pen;
+};
+
+
 // we want to grey out items in a combo box;
 // since Qt doesn't provide a function for this we derive a class
 class QComboBoxx
@@ -217,6 +232,7 @@ private slots:
   void previousFace();
   void previousFont();
   void previousInstance();
+  void zoom();
 
 private:
   Engine* engine;
@@ -258,6 +274,7 @@ private:
 
   QDoubleSpinBox *sizeDoubleSpinBox;
 
+  QGraphicsScene *glyphScene;
   QGraphicsView *glyphView;
 
   QGridLayout *fontLayout;