Add labels for font size.

Created a new function that checks for font size against the contrast and passes the relevant label to the frontend.

src/contents/ui/MainPage.qml

@@ -47,7 +47,7 @@ Kirigami.ScrollablePage {
         Kirigami.Heading {
             level: 1
             font.bold: true
-            text: i18n("Font size: %1", Kontrast.fontSize)
+            text: i18n("%1", Kontrast.fontSizeLabel)
 
             color: Kontrast.textColor
             wrapMode: Text.WordWrap
@@ -243,7 +243,7 @@ Kirigami.ScrollablePage {
             QQC2.Slider {
                 from: 1
                 value: Kontrast.fontSize
-                to: 72
+                to: 24
                 onMoved: Kontrast.fontSize = value
             }
         }

src/kontrast.cpp

@@ -9,8 +9,10 @@
 #include <QDebug>
 #include <QRandomGenerator>
 #include <QtMath>
+#include <iostream>
 
 #ifdef QT_DBUS_LIB
+#include <KLocalizedString>
 #include <QDBusConnection>
 #include <QDBusMessage>
 #include <QDBusMetaType>
@@ -66,6 +68,7 @@ void Kontrast::setTextColor(const QColor textColor)
     m_textColor = textColor;
     Q_EMIT textColorChanged();
     Q_EMIT contrastChanged();
+    Q_EMIT fontSizeChanged();
 }
 
 int Kontrast::textHue() const
@@ -81,6 +84,7 @@ void Kontrast::setTextHue(int hue)
     m_textColor.setHsl(hue, m_textColor.hslSaturation(), m_textColor.lightness());
     Q_EMIT textColorChanged();
     Q_EMIT contrastChanged();
+    Q_EMIT fontSizeChanged();
 }
 
 int Kontrast::textLightness() const
@@ -96,6 +100,7 @@ void Kontrast::setTextLightness(int lightness)
     m_textColor.setHsl(m_textColor.hslHue(), m_textColor.hslSaturation(), lightness);
     Q_EMIT textColorChanged();
     Q_EMIT contrastChanged();
+    Q_EMIT fontSizeChanged();
 }
 
 int Kontrast::textSaturation() const
@@ -111,6 +116,7 @@ void Kontrast::setTextSaturation(int saturation)
     m_textColor.setHsl(m_textColor.hslHue(), saturation, m_textColor.lightness());
     Q_EMIT textColorChanged();
     Q_EMIT contrastChanged();
+    Q_EMIT fontSizeChanged();
 }
 
 int Kontrast::fontSize() const
@@ -141,6 +147,7 @@ void Kontrast::setBackgroundColor(const QColor backgroundColor)
     m_backgroundColor = backgroundColor;
     Q_EMIT backgroundColorChanged();
     Q_EMIT contrastChanged();
+    Q_EMIT fontSizeChanged();
 }
 
 int Kontrast::backgroundHue() const
@@ -156,6 +163,7 @@ void Kontrast::setBackgroundHue(int hue)
     m_backgroundColor.setHsl(hue, m_backgroundColor.hslSaturation(), m_backgroundColor.lightness());
     Q_EMIT backgroundColorChanged();
     Q_EMIT contrastChanged();
+    Q_EMIT fontSizeChanged();
 }
 
 int Kontrast::backgroundLightness() const
@@ -171,6 +179,7 @@ void Kontrast::setBackgroundLightness(int lightness)
     m_backgroundColor.setHsl(m_backgroundColor.hslHue(), m_backgroundColor.hslSaturation(), lightness);
     Q_EMIT backgroundColorChanged();
     Q_EMIT contrastChanged();
+    Q_EMIT fontSizeChanged();
 }
 
 int Kontrast::backgroundSaturation() const
@@ -186,6 +195,7 @@ void Kontrast::setBackgroundSaturation(int saturation)
     m_backgroundColor.setHsl(m_backgroundColor.hslHue(), saturation, m_backgroundColor.lightness());
     Q_EMIT backgroundColorChanged();
     Q_EMIT contrastChanged();
+    Q_EMIT fontSizeChanged();
 }
 
 qreal luminosity(const QColor color)
@@ -224,6 +234,7 @@ void Kontrast::random()
     Q_EMIT backgroundColorChanged();
     Q_EMIT textColorChanged();
     Q_EMIT contrastChanged();
+    Q_EMIT fontSizeChanged();
 }
 
 void Kontrast::reverse()
@@ -234,6 +245,7 @@ void Kontrast::reverse()
     Q_EMIT backgroundColorChanged();
     Q_EMIT textColorChanged();
     Q_EMIT contrastChanged();
+    Q_EMIT fontSizeChanged();
 }
 
 QColor Kontrast::displayTextColor() const
@@ -307,3 +319,36 @@ void Kontrast::gotColorResponse(uint response, const QVariantMap &results)
     Q_UNUSED(results);
 #endif
 }
+
+Kontrast::ContrastQualities Kontrast::getContrastQualities()
+{
+    qreal contrast = Kontrast::contrast();
+
+    if (contrast > 7.0) {
+        return ContrastQualities{Perfect, Perfect, Perfect};
+    } else if (contrast > 4.5) {
+        return ContrastQualities{Good, Good, Perfect};
+    } else if (contrast > 3.0) {
+        return ContrastQualities{Bad, Bad, Good};
+    } else {
+        return ContrastQualities{Bad, Bad, Bad};
+    }
+}
+
+QString Kontrast::getFontSizeQualityLabel()
+{
+    auto currentQualities = getContrastQualities();
+
+    if (m_fontSize >= 18) {
+        return i18n("Font size %1px is %2 with the current contrast", m_fontSize, getStringFromEnum(currentQualities.large).toLower());
+    } else if (m_fontSize > 13) {
+        return i18n("Font size %1px is %2 with the current contrast", m_fontSize, getStringFromEnum(currentQualities.medium).toLower());
+    } else {
+        return i18n("Font size %1px is %2 with the current contrast", m_fontSize, getStringFromEnum(currentQualities.small).toLower());
+    }
+}
+
+QString Kontrast::getStringFromEnum(Quality quality)
+{
+    return i18n(QMetaEnum::fromType<Quality>().valueToKey(quality));
+}

src/kontrast.h

@@ -9,6 +9,7 @@
 #include <KAboutData>
 #include <QColor>
 #include <QImage>
+#include <QMetaEnum>
 #include <QObject>
 
 /**
@@ -34,6 +35,8 @@ class Kontrast : public QObject
 
     Q_PROPERTY(int backgroundSaturation READ backgroundSaturation WRITE setBackgroundSaturation NOTIFY backgroundColorChanged)
 
+    Q_PROPERTY(QString fontSizeLabel READ getFontSizeQualityLabel NOTIFY fontSizeChanged)
+
     Q_PROPERTY(int backgroundLightness READ backgroundLightness WRITE setBackgroundLightness NOTIFY backgroundColorChanged)
 
     Q_PROPERTY(qreal contrast READ contrast NOTIFY contrastChanged)
@@ -48,6 +51,16 @@ public:
     Kontrast(KAboutData about, QObject *parent = nullptr);
     virtual ~Kontrast() override = default;
 
+    enum Quality { Bad, Good, Perfect };
+
+    Q_ENUM(Quality)
+
+    struct ContrastQualities {
+        Quality small;
+        Quality medium;
+        Quality large;
+    };
+
     struct ColorRGB {
         double red;
         double green;
@@ -89,6 +102,8 @@ public:
 
     QColor grabbedColor() const;
 
+    QString getFontSizeQualityLabel();
+
     Q_INVOKABLE void random();
     Q_INVOKABLE void reverse();
     Q_INVOKABLE void grabColor();
@@ -110,6 +125,9 @@ private:
     QColor m_grabbedColor;
     int m_fontSize;
     KAboutData m_about;
+
+    ContrastQualities getContrastQualities();
+    static QString getStringFromEnum(Quality quality);
 };
 
 Q_DECLARE_METATYPE(Kontrast::ColorRGB)