Add support for creating System fonts

example/shared/src/commonMain/kotlin/com/splendo/kaluga/example/shared/stylable/TextStyles.kt

@@ -18,6 +18,10 @@
 package com.splendo.kaluga.example.shared.stylable
 
 import com.splendo.kaluga.resources.DefaultColors
+import com.splendo.kaluga.resources.FontStyle
+import com.splendo.kaluga.resources.FontTrait
+import com.splendo.kaluga.resources.FontWeight
+import com.splendo.kaluga.resources.createDefaultFont
 import com.splendo.kaluga.resources.defaultBoldFont
 import com.splendo.kaluga.resources.defaultFont
 import com.splendo.kaluga.resources.defaultItalicFont
@@ -42,6 +46,18 @@ object TextStyles {
     val defaultMonospaceText by lazy {
         KalugaTextStyle(defaultMonospaceFont, DefaultColors.dimGray, 12.0f)
     }
+    val semiBoldText by lazy {
+        KalugaTextStyle(createDefaultFont(FontWeight.SEMI_BOLD), DefaultColors.dimGray, 12.0f)
+    }
+    val serifText by lazy {
+        KalugaTextStyle(createDefaultFont(FontWeight.NORMAL, FontStyle.SERIF), DefaultColors.dimGray, 12.0f)
+    }
+    val italicBoldText by lazy {
+        KalugaTextStyle(createDefaultFont(FontWeight.BOLD, traits = setOf(FontTrait.ITALIC)), DefaultColors.dimGray, 12.0f)
+    }
+    val lightItalicMonospaceText by lazy {
+        KalugaTextStyle(createDefaultFont(FontWeight.LIGHT, FontStyle.MONOSPACE, traits = setOf(FontTrait.ITALIC)), DefaultColors.dimGray, 12.0f)
+    }
     val whiteText by lazy {
         KalugaTextStyle(defaultFont, DefaultColors.white, 12.0f)
     }

example/shared/src/commonMain/kotlin/com/splendo/kaluga/example/shared/viewmodel/resources/LabelViewModel.kt

@@ -76,6 +76,10 @@ class LabelViewModel(styledStringBuilderProvider: StyledStringBuilder.Provider)
             KalugaLabel.Plain("Bold Text", TextStyles.defaultBoldText),
             KalugaLabel.Plain("Italic Text", TextStyles.defaultItalicText),
             KalugaLabel.Plain("Monospace Text", TextStyles.defaultMonospaceText),
+            KalugaLabel.Plain("SemiBold Text", TextStyles.semiBoldText),
+            KalugaLabel.Plain("Serif Text", TextStyles.serifText),
+            KalugaLabel.Plain("Italic Bold Text", TextStyles.italicBoldText),
+            KalugaLabel.Plain("Light Italic Monospace Text", TextStyles.lightItalicMonospaceText),
             KalugaLabel.Plain("Red Text", TextStyles.redText),
             KalugaLabel.Plain("Opposite Aligned Text", TextStyles.oppositeText),
             KalugaLabel.Styled(

resources/api/androidLib/resources.api

@@ -1,4 +1,6 @@
 public final class com/splendo/kaluga/resources/AndroidFont {
+	public static final fun createDefaultFont (ILcom/splendo/kaluga/resources/FontStyle;Ljava/util/Set;)Landroid/graphics/Typeface;
+	public static synthetic fun createDefaultFont$default (ILcom/splendo/kaluga/resources/FontStyle;Ljava/util/Set;ILjava/lang/Object;)Landroid/graphics/Typeface;
 	public static final fun getDefaultBoldFont ()Landroid/graphics/Typeface;
 	public static final fun getDefaultFont ()Landroid/graphics/Typeface;
 	public static final fun getDefaultItalicFont ()Landroid/graphics/Typeface;
@@ -396,6 +398,38 @@ public abstract interface class com/splendo/kaluga/resources/FontLoader {
 	public abstract fun loadFont (Ljava/lang/String;Landroid/graphics/Typeface;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 }
 
+public final class com/splendo/kaluga/resources/FontStyle : java/lang/Enum {
+	public static final field DEFAULT Lcom/splendo/kaluga/resources/FontStyle;
+	public static final field MONOSPACE Lcom/splendo/kaluga/resources/FontStyle;
+	public static final field SERIF Lcom/splendo/kaluga/resources/FontStyle;
+	public static fun getEntries ()Lkotlin/enums/EnumEntries;
+	public static fun valueOf (Ljava/lang/String;)Lcom/splendo/kaluga/resources/FontStyle;
+	public static fun values ()[Lcom/splendo/kaluga/resources/FontStyle;
+}
+
+public final class com/splendo/kaluga/resources/FontTrait : java/lang/Enum {
+	public static final field ITALIC Lcom/splendo/kaluga/resources/FontTrait;
+	public static fun getEntries ()Lkotlin/enums/EnumEntries;
+	public static fun valueOf (Ljava/lang/String;)Lcom/splendo/kaluga/resources/FontTrait;
+	public static fun values ()[Lcom/splendo/kaluga/resources/FontTrait;
+}
+
+public final class com/splendo/kaluga/resources/FontWeight : java/lang/Enum {
+	public static final field BLACK Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field BOLD Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field EXTRA_BOLD Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field EXTRA_LIGHT Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field LIGHT Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field MEDIUM Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field NORMAL Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field SEMI_BOLD Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field THIN Lcom/splendo/kaluga/resources/FontWeight;
+	public static fun getEntries ()Lkotlin/enums/EnumEntries;
+	public final fun getValue ()I
+	public static fun valueOf (Ljava/lang/String;)Lcom/splendo/kaluga/resources/FontWeight;
+	public static fun values ()[Lcom/splendo/kaluga/resources/FontWeight;
+}
+
 public final class com/splendo/kaluga/resources/HSLColor {
 	public static final field Companion Lcom/splendo/kaluga/resources/HSLColor$Companion;
 	public fun <init> (DDDD)V
@@ -445,6 +479,11 @@ public abstract interface class com/splendo/kaluga/resources/KalugaColorLoader {
 	public abstract fun loadColor (Ljava/lang/String;Ljava/lang/Integer;)Ljava/lang/Integer;
 }
 
+public final class com/splendo/kaluga/resources/KalugaFontKt {
+	public static final fun createDefaultFont (Lcom/splendo/kaluga/resources/FontWeight;Lcom/splendo/kaluga/resources/FontStyle;Ljava/util/Set;)Landroid/graphics/Typeface;
+	public static synthetic fun createDefaultFont$default (Lcom/splendo/kaluga/resources/FontWeight;Lcom/splendo/kaluga/resources/FontStyle;Ljava/util/Set;ILjava/lang/Object;)Landroid/graphics/Typeface;
+}
+
 public final class com/splendo/kaluga/resources/KalugaImage {
 	public fun <init> (Landroid/graphics/drawable/Drawable;)V
 	public final fun component1 ()Landroid/graphics/drawable/Drawable;

resources/api/jvm/resources.api

@@ -374,6 +374,38 @@ public abstract interface class com/splendo/kaluga/resources/FontLoader {
 	public abstract fun loadFont (Ljava/lang/String;Lcom/splendo/kaluga/resources/KalugaFont;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
 }
 
+public final class com/splendo/kaluga/resources/FontStyle : java/lang/Enum {
+	public static final field DEFAULT Lcom/splendo/kaluga/resources/FontStyle;
+	public static final field MONOSPACE Lcom/splendo/kaluga/resources/FontStyle;
+	public static final field SERIF Lcom/splendo/kaluga/resources/FontStyle;
+	public static fun getEntries ()Lkotlin/enums/EnumEntries;
+	public static fun valueOf (Ljava/lang/String;)Lcom/splendo/kaluga/resources/FontStyle;
+	public static fun values ()[Lcom/splendo/kaluga/resources/FontStyle;
+}
+
+public final class com/splendo/kaluga/resources/FontTrait : java/lang/Enum {
+	public static final field ITALIC Lcom/splendo/kaluga/resources/FontTrait;
+	public static fun getEntries ()Lkotlin/enums/EnumEntries;
+	public static fun valueOf (Ljava/lang/String;)Lcom/splendo/kaluga/resources/FontTrait;
+	public static fun values ()[Lcom/splendo/kaluga/resources/FontTrait;
+}
+
+public final class com/splendo/kaluga/resources/FontWeight : java/lang/Enum {
+	public static final field BLACK Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field BOLD Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field EXTRA_BOLD Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field EXTRA_LIGHT Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field LIGHT Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field MEDIUM Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field NORMAL Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field SEMI_BOLD Lcom/splendo/kaluga/resources/FontWeight;
+	public static final field THIN Lcom/splendo/kaluga/resources/FontWeight;
+	public static fun getEntries ()Lkotlin/enums/EnumEntries;
+	public final fun getValue ()I
+	public static fun valueOf (Ljava/lang/String;)Lcom/splendo/kaluga/resources/FontWeight;
+	public static fun values ()[Lcom/splendo/kaluga/resources/FontWeight;
+}
+
 public final class com/splendo/kaluga/resources/HSLColor {
 	public static final field Companion Lcom/splendo/kaluga/resources/HSLColor$Companion;
 	public fun <init> (DDDD)V
@@ -420,6 +452,8 @@ public abstract interface class com/splendo/kaluga/resources/ImageLoader {
 }
 
 public final class com/splendo/kaluga/resources/JvmFont {
+	public static final fun createDefaultFont (ILcom/splendo/kaluga/resources/FontStyle;Ljava/util/Set;)Lcom/splendo/kaluga/resources/KalugaFont;
+	public static synthetic fun createDefaultFont$default (ILcom/splendo/kaluga/resources/FontStyle;Ljava/util/Set;ILjava/lang/Object;)Lcom/splendo/kaluga/resources/KalugaFont;
 	public static final fun getDefaultBoldFont ()Lcom/splendo/kaluga/resources/KalugaFont;
 	public static final fun getDefaultFont ()Lcom/splendo/kaluga/resources/KalugaFont;
 	public static final fun getDefaultItalicFont ()Lcom/splendo/kaluga/resources/KalugaFont;
@@ -449,6 +483,11 @@ public final class com/splendo/kaluga/resources/KalugaFont {
 	public fun <init> ()V
 }
 
+public final class com/splendo/kaluga/resources/KalugaFontKt {
+	public static final fun createDefaultFont (Lcom/splendo/kaluga/resources/FontWeight;Lcom/splendo/kaluga/resources/FontStyle;Ljava/util/Set;)Lcom/splendo/kaluga/resources/KalugaFont;
+	public static synthetic fun createDefaultFont$default (Lcom/splendo/kaluga/resources/FontWeight;Lcom/splendo/kaluga/resources/FontStyle;Ljava/util/Set;ILjava/lang/Object;)Lcom/splendo/kaluga/resources/KalugaFont;
+}
+
 public final class com/splendo/kaluga/resources/KalugaImage {
 	public fun <init> ()V
 }

resources/src/androidLibMain/kotlin/KalugaFont.kt

@@ -20,6 +20,7 @@
 package com.splendo.kaluga.resources
 
 import android.graphics.Typeface
+import android.os.Build
 
 /**
  * Class describing a font
@@ -45,3 +46,34 @@ actual val defaultItalicFont: KalugaFont get() = Typeface.create(Typeface.DEFAUL
  * The default monospace system [KalugaFont]
  */
 actual val defaultMonospaceFont: KalugaFont get() = Typeface.MONOSPACE
+
+/**
+ * Creates a system font with a given weight, [FontStyle] and [FontTrait]
+ * @param weight the weight to apply. Must be in range [1, 100]
+ * @param style the [FontStyle] to apply
+ * @param traits the set of [FontTrait] to apply
+ * @return a [KalugaFont] representing the system font with the given specifications
+ */
+actual fun createDefaultFont(weight: Int, style: FontStyle, traits: Set<FontTrait>): KalugaFont {
+    val typeface = when (style) {
+        FontStyle.DEFAULT -> Typeface.DEFAULT
+        FontStyle.SERIF -> Typeface.SERIF
+        FontStyle.MONOSPACE -> Typeface.MONOSPACE
+    }
+    return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+        Typeface.create(typeface, weight, FontTrait.ITALIC in traits)
+    } else {
+        val typefaceStyle = traits.fold(
+            if (weight >= FontWeight.SEMI_BOLD.value) {
+                Typeface.BOLD
+            } else {
+                Typeface.NORMAL
+            },
+        ) { acc, trait ->
+            acc or when (trait) {
+                FontTrait.ITALIC -> Typeface.ITALIC
+            }
+        }
+        Typeface.create(typeface, typefaceStyle)
+    }
+}

resources/src/commonMain/kotlin/KalugaFont.kt

@@ -47,3 +47,69 @@ expect val defaultItalicFont: KalugaFont
  * The default monospace system [KalugaFont]
  */
 expect val defaultMonospaceFont: KalugaFont
+
+/**
+ * Style of the system font
+ */
+enum class FontStyle {
+
+    /**
+     * Default system font style
+     */
+    DEFAULT,
+
+    /**
+     * Serif system font style
+     */
+    SERIF,
+
+    /**
+     * Monospace system font style
+     */
+    MONOSPACE,
+}
+
+/**
+ * Trait to add to a system font
+ */
+enum class FontTrait {
+
+    /**
+     * Makes the system font appear in italics
+     */
+    ITALIC,
+}
+
+/**
+ * Font weights as defined by [W3](https://www.w3.org/TR/css-fonts-4/#font-weight-prop)
+ * @property value the value of the weight. Must be in range [1, 100]
+ */
+enum class FontWeight(val value: Int) {
+    THIN(100),
+    EXTRA_LIGHT(200),
+    LIGHT(300),
+    NORMAL(400),
+    MEDIUM(500),
+    SEMI_BOLD(600),
+    BOLD(700),
+    EXTRA_BOLD(800),
+    BLACK(900),
+}
+
+/**
+ * Creates a system font with a given [FontWeight], [FontStyle] and [FontTrait]
+ * @param weight the [FontWeight] to apply
+ * @param style the [FontStyle] to apply
+ * @param traits the set of [FontTrait] to apply
+ * @return a [KalugaFont] representing the system font with the given specifications
+ */
+fun createDefaultFont(weight: FontWeight, style: FontStyle = FontStyle.DEFAULT, traits: Set<FontTrait> = emptySet()): KalugaFont = createDefaultFont(weight.value, style, traits)
+
+/**
+ * Creates a system font with a given weight, [FontStyle] and [FontTrait]
+ * @param weight the weight to apply. Must be in range [1, 100]
+ * @param style the [FontStyle] to apply
+ * @param traits the set of [FontTrait] to apply
+ * @return a [KalugaFont] representing the system font with the given specifications
+ */
+expect fun createDefaultFont(weight: Int, style: FontStyle = FontStyle.DEFAULT, traits: Set<FontTrait> = emptySet()): KalugaFont

resources/src/iosMain/kotlin/KalugaFont.kt

@@ -18,7 +18,19 @@
 package com.splendo.kaluga.resources
 
 import platform.UIKit.UIFont
+import platform.UIKit.UIFontDescriptorSystemDesignDefault
+import platform.UIKit.UIFontDescriptorSystemDesignMonospaced
+import platform.UIKit.UIFontDescriptorSystemDesignSerif
+import platform.UIKit.UIFontDescriptorTraitItalic
+import platform.UIKit.UIFontWeightBlack
+import platform.UIKit.UIFontWeightBold
+import platform.UIKit.UIFontWeightHeavy
+import platform.UIKit.UIFontWeightLight
+import platform.UIKit.UIFontWeightMedium
 import platform.UIKit.UIFontWeightRegular
+import platform.UIKit.UIFontWeightSemibold
+import platform.UIKit.UIFontWeightThin
+import platform.UIKit.UIFontWeightUltraLight
 import platform.UIKit.labelFontSize
 
 /**
@@ -45,3 +57,70 @@ actual val defaultItalicFont: KalugaFont get() = UIFont.italicSystemFontOfSize(U
  * The default monospace system [KalugaFont]
  */
 actual val defaultMonospaceFont: KalugaFont get() = UIFont.monospacedSystemFontOfSize(UIFont.labelFontSize, UIFontWeightRegular)
+
+/**
+ * Creates a system font with a given weight, [FontStyle] and [FontTrait]
+ * @param weight the weight to apply. Must be in range [1, 100]
+ * @param style the [FontStyle] to apply
+ * @param traits the set of [FontTrait] to apply
+ * @return a [KalugaFont] representing the system font with the given specifications
+ */
+actual fun createDefaultFont(weight: Int, style: FontStyle, traits: Set<FontTrait>): KalugaFont {
+    val calculateWeight: (Double, Double, FontWeight) -> Double = { uiFontWeight, factor, fontWeight ->
+        val difference = factor * ((fontWeight.value - weight).toDouble() / 100.0)
+        uiFontWeight - difference
+    }
+    // UIFontWeight is rather weird in that it is not evenly distributed.
+    // For instance, UIFontWeightRegular is 0.0, UIFontWeightMedium is 0.23000000417232513, and UIFontWeightLight is -0.4000000059604645
+    // To account for these inconsistencies, we interpolate between the steps
+    val actualWeight = when {
+        weight <= FontWeight.THIN.value -> {
+            // Not a bug, iOS flips these names
+            calculateWeight(UIFontWeightUltraLight, UIFontWeightThin - UIFontWeightUltraLight, FontWeight.THIN)
+        }
+        weight <= FontWeight.EXTRA_LIGHT.value -> {
+            calculateWeight(UIFontWeightThin, UIFontWeightThin - UIFontWeightUltraLight, FontWeight.EXTRA_LIGHT)
+        }
+        weight <= FontWeight.LIGHT.value -> {
+            calculateWeight(UIFontWeightLight, UIFontWeightLight - UIFontWeightThin, FontWeight.LIGHT)
+        }
+        weight <= FontWeight.NORMAL.value -> {
+            calculateWeight(UIFontWeightRegular, UIFontWeightRegular - UIFontWeightLight, FontWeight.NORMAL)
+        }
+        weight <= FontWeight.MEDIUM.value -> {
+            calculateWeight(UIFontWeightMedium, UIFontWeightMedium - UIFontWeightRegular, FontWeight.MEDIUM)
+        }
+        weight <= FontWeight.SEMI_BOLD.value -> {
+            calculateWeight(UIFontWeightSemibold, UIFontWeightSemibold - UIFontWeightMedium, FontWeight.SEMI_BOLD)
+        }
+        weight <= FontWeight.BOLD.value -> {
+            calculateWeight(UIFontWeightBold, UIFontWeightBold - UIFontWeightSemibold, FontWeight.BOLD)
+        }
+        weight <= FontWeight.EXTRA_BOLD.value -> {
+            calculateWeight(UIFontWeightHeavy, UIFontWeightHeavy - UIFontWeightBold, FontWeight.EXTRA_BOLD)
+        }
+        weight <= FontWeight.EXTRA_LIGHT.value -> {
+            calculateWeight(UIFontWeightBlack, UIFontWeightBlack - UIFontWeightHeavy, FontWeight.BLACK)
+        }
+        else -> {
+            val difference = ((weight - FontWeight.BLACK.value).toDouble() / 100.0) * UIFontWeightBlack - UIFontWeightHeavy
+            UIFontWeightBlack + difference
+        }
+    }
+    val font = UIFont.systemFontOfSize(UIFont.labelFontSize, actualWeight)
+    val design = when (style) {
+        FontStyle.DEFAULT -> UIFontDescriptorSystemDesignDefault
+        FontStyle.SERIF -> UIFontDescriptorSystemDesignSerif
+        FontStyle.MONOSPACE -> UIFontDescriptorSystemDesignMonospaced
+    }
+    val symbolicTraits = traits.fold(0U) { acc, trait ->
+        when (trait) {
+            FontTrait.ITALIC -> acc or UIFontDescriptorTraitItalic
+        }
+    }
+    return UIFont.fontWithDescriptor(
+        font.fontDescriptor.fontDescriptorWithDesign(design)!!
+            .fontDescriptorWithSymbolicTraits(symbolicTraits)!!,
+        UIFont.labelFontSize,
+    )
+}

resources/src/jsMain/kotlin/KalugaFont.kt

@@ -41,3 +41,12 @@ actual val defaultItalicFont: KalugaFont get() = KalugaFont()
  * The default monospace system [KalugaFont]
  */
 actual val defaultMonospaceFont: KalugaFont get() = KalugaFont()
+
+/**
+ * Creates a system font with a given weight, [FontStyle] and [FontTrait]
+ * @param weight the weight to apply. Must be in range [1, 100]
+ * @param style the [FontStyle] to apply
+ * @param traits the set of [FontTrait] to apply
+ * @return a [KalugaFont] representing the system font with the given specifications
+ */
+actual fun createDefaultFont(weight: Int, style: FontStyle, traits: Set<FontTrait>): KalugaFont = KalugaFont()

resources/src/jvmMain/kotlin/KalugaFont.kt

@@ -43,3 +43,12 @@ actual val defaultItalicFont: KalugaFont get() = KalugaFont()
  * The default monospace system [KalugaFont]
  */
 actual val defaultMonospaceFont: KalugaFont get() = KalugaFont()
+
+/**
+ * Creates a system font with a given weight, [FontStyle] and [FontTrait]
+ * @param weight the weight to apply. Must be in range [1, 100]
+ * @param style the [FontStyle] to apply
+ * @param traits the set of [FontTrait] to apply
+ * @return a [KalugaFont] representing the system font with the given specifications
+ */
+actual fun createDefaultFont(weight: Int, style: FontStyle, traits: Set<FontTrait>): KalugaFont = KalugaFont()