Add headingTypeface, headingTextSizes to SpannableTheme (#51)

* Add headingTypeface to SpannableTheme, use a custom heading typeface in the sample app

* Add headingTextSizes

* Switching to headingTextSizeMultipliers, adding validating annotations, adding example

* Consolidate logic, add crash if header index is out of bounds

library/src/main/java/ru/noties/markwon/spans/SpannableTheme.java

@@ -12,9 +12,13 @@ import android.support.annotation.FloatRange;
 import android.support.annotation.IntRange;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.support.annotation.Size;
 import android.text.TextPaint;
 import android.util.TypedValue;
 
+import java.util.Arrays;
+import java.util.Locale;
+
 @SuppressWarnings("WeakerAccess")
 public class SpannableTheme {
 
@@ -173,6 +177,13 @@ public class SpannableTheme {
     // by default, text color with `HEADING_DEF_BREAK_COLOR_ALPHA` applied alpha
     protected final int headingBreakColor;
 
+    // by default, whatever typeface is set on the TextView
+    protected final Typeface headingTypeface;
+
+    // by default, we use standard multipliers from the HTML spec (see HEADING_SIZES for values).
+    // this library supports 6 heading sizes, so make sure the array you pass here has 6 elements.
+    protected final float[] headingTextSizeMultipliers;
+
     // by default `SCRIPT_DEF_TEXT_SIZE_RATIO`
     protected final float scriptTextSizeRatio;
 
@@ -214,6 +225,8 @@ public class SpannableTheme {
         this.codeTextSize = builder.codeTextSize;
         this.headingBreakHeight = builder.headingBreakHeight;
         this.headingBreakColor = builder.headingBreakColor;
+        this.headingTypeface = builder.headingTypeface;
+        this.headingTextSizeMultipliers = builder.headingTextSizeMultipliers;
         this.scriptTextSizeRatio = builder.scriptTextSizeRatio;
         this.thematicBreakColor = builder.thematicBreakColor;
         this.thematicBreakHeight = builder.thematicBreakHeight;
@@ -368,8 +381,23 @@ public class SpannableTheme {
     }
 
     public void applyHeadingTextStyle(@NonNull Paint paint, @IntRange(from = 1, to = 6) int level) {
-        paint.setFakeBoldText(true);
-        paint.setTextSize(paint.getTextSize() * HEADING_SIZES[level - 1]);
+        if (headingTypeface == null) {
+            paint.setFakeBoldText(true);
+        } else {
+            paint.setTypeface(headingTypeface);
+        }
+        final float[] textSizes = headingTextSizeMultipliers != null
+                ? headingTextSizeMultipliers
+                : HEADING_SIZES;
+
+        if (textSizes != null && textSizes.length >= level) {
+            paint.setTextSize(paint.getTextSize() * textSizes[level - 1]);
+        } else {
+            throw new IllegalStateException(String.format(
+                    Locale.US,
+                    "Supplied heading level: %d is invalid, where configured heading sizes are: `%s`",
+                    level, Arrays.toString(textSizes)));
+        }
     }
 
     public void applyHeadingBreakStyle(@NonNull Paint paint) {
@@ -491,6 +519,8 @@ public class SpannableTheme {
         private int codeTextSize;
         private int headingBreakHeight = -1;
         private int headingBreakColor;
+        private Typeface headingTypeface;
+        private float[] headingTextSizeMultipliers;
         private float scriptTextSizeRatio;
         private int thematicBreakColor;
         private int thematicBreakHeight = -1;
@@ -520,6 +550,8 @@ public class SpannableTheme {
             this.codeTextSize = theme.codeTextSize;
             this.headingBreakHeight = theme.headingBreakHeight;
             this.headingBreakColor = theme.headingBreakColor;
+            this.headingTypeface = theme.headingTypeface;
+            this.headingTextSizeMultipliers = theme.headingTextSizeMultipliers;
             this.scriptTextSizeRatio = theme.scriptTextSizeRatio;
             this.thematicBreakColor = theme.thematicBreakColor;
             this.thematicBreakHeight = theme.thematicBreakHeight;
@@ -634,6 +666,18 @@ public class SpannableTheme {
             return this;
         }
 
+        @NonNull
+        public Builder headingTypeface(@NonNull Typeface headingTypeface) {
+            this.headingTypeface = headingTypeface;
+            return this;
+        }
+
+        @NonNull
+        public Builder headingTextSizeMultipliers(@Size(6) @NonNull float[] headingTextSizeMultipliers) {
+            this.headingTextSizeMultipliers = headingTextSizeMultipliers;
+            return this;
+        }
+
         @NonNull
         public Builder scriptTextSizeRatio(@FloatRange(from = .0F, to = Float.MAX_VALUE) float scriptTextSizeRatio) {
             this.scriptTextSizeRatio = scriptTextSizeRatio;

sample-custom-extension/src/main/java/ru/noties/markwon/sample/extension/MainActivity.java

@@ -1,6 +1,7 @@
 package ru.noties.markwon.sample.extension;
 
 import android.app.Activity;
+import android.graphics.Typeface;
 import android.os.Bundle;
 import android.widget.TextView;
 
@@ -13,6 +14,7 @@ import java.util.Arrays;
 
 import ru.noties.markwon.SpannableBuilder;
 import ru.noties.markwon.SpannableConfiguration;
+import ru.noties.markwon.spans.SpannableTheme;
 import ru.noties.markwon.tasklist.TaskListExtension;
 
 public class MainActivity extends Activity {
@@ -50,9 +52,16 @@ public class MainActivity extends Activity {
         // better to provide a valid fallback option
         final IconSpanProvider spanProvider = IconSpanProvider.create(this, 0);
 
+        final float[] textSizeMultipliers = new float[]{3f, 2f, 1.5f, 1f, .5f, .25f};
+        SpannableConfiguration configuration = SpannableConfiguration.builder(this)
+                .theme(SpannableTheme.builder()
+                        .headingTypeface(Typeface.MONOSPACE)
+                        .headingTextSizeMultipliers(textSizeMultipliers)
+                        .build())
+                .build();
         // create an instance of visitor to process parsed markdown
         final IconVisitor visitor = new IconVisitor(
-                SpannableConfiguration.create(this),
+                configuration,
                 builder,
                 spanProvider
         );

sample-custom-extension/src/main/res/layout/activity_main.xml

@@ -11,6 +11,7 @@
         android:layout_height="wrap_content"
         android:padding="8dip"
         android:textAppearance="?android:attr/textAppearanceMedium"
+        android:textSize="15sp"
         tools:text="@string/input"/>
 
-</ScrollView>
+</ScrollView>

sample-custom-extension/src/main/res/values/strings.xml

@@ -6,6 +6,7 @@
         # Hello! @ic-android-black-24\n\n
         Home 36 black: @ic-home-black-36\n\n
         Memory 48 black: @ic-memory-black-48\n\n
+        ### I AM ANOTHER HEADER\n\n
         Sentiment Satisfied 64 red: @ic-sentiment_satisfied-red-64
     ]]>
     </string>