Add text align and baseline

2 files changed, 124 insertions, 9 deletions

diff --git a/src/context2d.cpp b/src/context2d.cpp
index 7d275fa..726fa4e 100644
--- a/src/context2d.cpp
+++ b/src/context2d.cpp
@@ -43,6 +43,7 @@
 static const double Q_PI   = 3.14159265358979323846;   // pi
 
 #include <QGraphicsItem>
+#include <QApplication>
 #include <QStyleOptionGraphicsItem>
 #include <QGraphicsDropShadowEffect>
 
@@ -477,17 +478,78 @@ void Context2D::setShadowColor(const QString &str)
 QString Context2D::textBaseline()
 {
     switch(m_state.textBaseline) {
+    case Context2D::Alphabetic:
+        return QLatin1String("alphabetic");
+    case Context2D::Hanging:
+        return QLatin1String("hanging");
+    case Context2D::Bottom:
+        return QLatin1String("bottom");
+    case Context2D::Top:
+        return QLatin1String("top");
+    case Context2D::Middle:
+        return QLatin1String("middle");
     default:
-        return "middle";
+        Q_ASSERT("invalid value");
+        return QLatin1String("start");
     }
 }
 
-void Context2D::setTextBaseline(const QString &)
+void Context2D::setTextBaseline(const QString &baseline)
+{
+    if (baseline==QLatin1String("alphabetic"))
+        m_state.textBaseline = Context2D::Alphabetic;
+    else if (baseline == QLatin1String("hanging"))
+        m_state.textBaseline = Context2D::Hanging;
+    else if (baseline == QLatin1String("top"))
+        m_state.textBaseline = Context2D::Top;
+    else if (baseline == QLatin1String("bottom"))
+        m_state.textBaseline = Context2D::Bottom;
+    else if (baseline == QLatin1String("middle"))
+        m_state.textBaseline = Context2D::Middle;
+    else {
+        m_state.textBaseline = Context2D::Alphabetic;
+        qWarning() << ("Context2D: invalid baseline:" + baseline);
+    }
+    m_state.flags |= DirtyTextBaseline;
+}
+
+QString Context2D::textAlign()
 {
-    qDebug("Baseline not implemented");
+    switch(m_state.textAlign) {
+    case Context2D::Left:
+        return QLatin1String("left");
+    case Context2D::Right:
+        return QLatin1String("right");
+    case Context2D::Center:
+        return QLatin1String("center");
+    case Context2D::Start:
+        return QLatin1String("start");
+    case Context2D::End:
+        return QLatin1String("end");
+    default:
+        Q_ASSERT("invalid value");
+        qWarning() << ("Context2D::invalid textAlign");
+        return QLatin1String("start");
+    }
+}
 
+void Context2D::setTextAlign(const QString &baseline)
+{
+    if (baseline==QLatin1String("start"))
+        m_state.textAlign = Context2D::Start;
+    else if (baseline == QLatin1String("end"))
+        m_state.textAlign = Context2D::End;
+    else if (baseline == QLatin1String("left"))
+        m_state.textAlign = Context2D::Left;
+    else if (baseline == QLatin1String("right"))
+        m_state.textAlign = Context2D::Right;
+    else if (baseline == QLatin1String("center"))
+        m_state.textAlign = Context2D::Center;
+    else {
+        m_state.textAlign= Context2D::Start;
+        qWarning("Context2D: invalid text align");
+    }
     // ### alphabetic, ideographic, hanging
-
     m_state.flags |= DirtyTextBaseline;
 }
 
@@ -563,9 +625,46 @@ void Context2D::fillRect(qreal x, qreal y, qreal w, qreal h)
     scheduleChange();
 }
 
+int Context2D::baseLineOffset(Context2D::TextBaseLine value, const QFontMetrics &metrics)
+{
+    int offset;
+    switch(value) {
+    case Context2D::Top:
+        break;
+    case Context2D::Alphabetic:
+    case Context2D::Middle:
+    case Context2D::Hanging:
+        offset = metrics.ascent();
+        break;
+    case Context2D::Bottom:
+        offset = metrics.height();
+       break;
+    }
+    return offset;
+}
+
+int Context2D::textAlignOffset(Context2D::TextAlign value, const QFontMetrics &metrics, const QString &text)
+{
+    int offset;
+    if (value == Context2D::Start)
+        value = qApp->layoutDirection() == Qt::LeftToRight ? Context2D::Left : Context2D::Right;
+    else if (value == Context2D::End)
+        value = qApp->layoutDirection() == Qt::LeftToRight ? Context2D::Right: Context2D::Left;
+    switch(value) {
+    case Context2D::Center:
+        offset = metrics.width(text)/2;
+        break;
+    case Context2D::Right:
+        offset = metrics.width(text);
+    case Context2D::Left:
+    default:
+        break;
+    }
+    return offset;
+}
+
 void Context2D::fillText(const QString &text, qreal x, qreal y)
 {
-    qDebug("here");
     beginPainting();
     m_painter.save();
     m_painter.setPen(QPen(m_state.fillStyle, m_state.lineWidth));
@@ -573,8 +672,10 @@ void Context2D::fillText(const QString &text, qreal x, qreal y)
     QFont font;
     font.setBold(true);
     m_painter.setFont(m_state.font);
+    int yoffset = baseLineOffset(m_state.textBaseline, m_painter.fontMetrics());
+    int xoffset = textAlignOffset(m_state.textAlign, m_painter.fontMetrics(), text);
     QTextOption opt; // Adjust baseLine etc
-    m_painter.drawText(QRectF(x, y, m_pixmap.width(), m_painter.fontMetrics().height()), text, opt);
+    m_painter.drawText(QRectF(x-xoffset, y-yoffset, m_pixmap.width(), m_painter.fontMetrics().height()), text, opt);
     m_painter.restore();
     scheduleChange();
 }
@@ -589,7 +690,11 @@ void Context2D::strokeText(const QString &text, qreal x, qreal y)
     QPainterPath textPath;
     QFont font = m_state.font;
     font.setStyleStrategy(QFont::ForceOutline);
-    textPath.addText(x, y, font, text);
+    m_painter.setFont(font);
+    const QFontMetrics &metrics = m_painter.fontMetrics();
+    int yoffset = baseLineOffset(m_state.textBaseline, metrics);
+    int xoffset = textAlignOffset(m_state.textAlign, metrics, text);
+    textPath.addText(x-xoffset, y-yoffset+metrics.ascent(), font, text);
     m_painter.strokePath(textPath, QPen(m_state.fillStyle, m_state.lineWidth));
     m_painter.restore();
     scheduleChange();
diff --git a/src/context2d.h b/src/context2d.h
index 46b0644..57cf922 100644
--- a/src/context2d.h
+++ b/src/context2d.h
@@ -124,6 +124,10 @@ class Context2D : public QObject
     // fonts
     Q_PROPERTY(QString font READ font WRITE setFont)
     Q_PROPERTY(QString textBaseline READ textBaseline WRITE setTextBaseline)
+    Q_PROPERTY(QString textAlign READ textAlign WRITE setTextAlign)
+
+    enum TextBaseLine { Alphabetic=0, Top, Middle, Bottom, Hanging};
+    enum TextAlign { Start=0, End, Left, Right, Center};
 
 public:
     Context2D(QObject *parent = 0);
@@ -165,6 +169,8 @@ public:
     QString font();
     void setTextBaseline(const QString &font);
     QString textBaseline();
+    void setTextAlign(const QString &font);
+    QString textAlign();
 
     // shadows
     qreal shadowOffsetX() const; // (default 0)
@@ -285,10 +291,14 @@ private:
         QColor shadowColor;
         QPainter::CompositionMode globalCompositeOperation;
         QFont font;
-        int textAlign;
-        int textBaseline;
+        Context2D::TextAlign textAlign;
+        Context2D::TextBaseLine textBaseline;
         int flags;
     };
+
+    int baseLineOffset(Context2D::TextBaseLine value, const QFontMetrics &metrics);
+    int textAlignOffset(Context2D::TextAlign value, const QFontMetrics &metrics, const QString &string);
+
     State m_state;
     QStack<State> m_stateStack;
     QPixmap m_pixmap;