allow increasing text editor font size with gestures

app/build.gradle

@@ -53,4 +53,5 @@ android {
 dependencies {
     implementation 'com.simplemobiletools:commons:5.6.17'
     implementation 'com.github.Stericson:RootTools:df729dcb13'
+    implementation 'com.alexvasilkov:gesture-views:2.5.2'
 }

app/src/main/kotlin/com/simplemobiletools/filemanager/pro/activities/MainActivity.kt

@@ -248,7 +248,7 @@ class MainActivity : SimpleActivity() {
     }
 
     private fun launchAbout() {
-        val licenses = LICENSE_GLIDE or LICENSE_PATTERN or LICENSE_REPRINT
+        val licenses = LICENSE_GLIDE or LICENSE_PATTERN or LICENSE_REPRINT or LICENSE_GESTURE_VIEWS
 
         val faqItems = arrayListOf(
                 FAQItem(R.string.faq_3_title_commons, R.string.faq_3_text_commons),

app/src/main/kotlin/com/simplemobiletools/filemanager/pro/views/GestureTextView.kt

@@ -0,0 +1,72 @@
+package com.simplemobiletools.filemanager.pro.views
+
+import android.content.Context
+import android.util.AttributeSet
+import android.util.TypedValue
+import android.view.MotionEvent
+import androidx.appcompat.widget.AppCompatTextView
+import com.alexvasilkov.gestures.GestureController
+import com.alexvasilkov.gestures.State
+import com.alexvasilkov.gestures.views.interfaces.GestureView
+import com.simplemobiletools.commons.extensions.getAdjustedPrimaryColor
+import com.simplemobiletools.filemanager.pro.extensions.config
+
+// taken from
+// https://github.com/alexvasilkov/GestureViews/blob/f0a4c266e31dcad23bd0d9013531bc1c501b9c9f/sample/src/main/java/com/alexvasilkov/gestures/sample/ex/custom/text/GestureTextView.java
+class GestureTextView @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyle: Int = 0) : AppCompatTextView(context, attrs, defStyle), GestureView {
+    private val controller: GestureController = GestureController(this)
+    private var origSize = 0f
+    private var size = 0f
+
+    init {
+        controller.settings.setOverzoomFactor(1f).isPanEnabled = false
+        controller.settings.initFromAttributes(context, attrs)
+        controller.addOnStateChangeListener(object : GestureController.OnStateChangeListener {
+            override fun onStateChanged(state: State) {
+                applyState(state)
+            }
+
+            override fun onStateReset(oldState: State, newState: State) {
+                applyState(newState)
+            }
+        })
+
+        origSize = textSize
+        setTextColor(context.config.textColor)
+        setLinkTextColor(context.getAdjustedPrimaryColor())
+    }
+
+    override fun getController() = controller
+
+    override fun onTouchEvent(event: MotionEvent) = controller.onTouch(this, event)
+
+    override fun setTextSize(size: Float) {
+        super.setTextSize(size)
+        origSize = textSize
+        applyState(controller.state)
+    }
+
+    override fun setTextSize(unit: Int, size: Float) {
+        super.setTextSize(unit, size)
+        origSize = textSize
+        applyState(controller.state)
+    }
+
+    override fun onSizeChanged(width: Int, height: Int, oldWidth: Int, oldHeight: Int) {
+        super.onSizeChanged(width, height, oldWidth, oldHeight)
+        controller.settings.setViewport(width, height).setImage(width, height)
+        controller.updateState()
+    }
+
+    private fun applyState(state: State) {
+        var size = origSize * state.zoom
+        val maxSize = origSize * controller.stateController.getMaxZoom(state)
+        size = Math.max(origSize, Math.min(size, maxSize))
+
+        size = Math.round(size).toFloat()
+        if (!State.equals(this.size, size)) {
+            this.size = size
+            super.setTextSize(TypedValue.COMPLEX_UNIT_PX, size)
+        }
+    }
+}

app/src/main/res/layout/activity_read_text.xml

@@ -3,15 +3,16 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/read_text_holder"
     android:layout_width="match_parent"
-    android:layout_height="wrap_content">
+    android:layout_height="match_parent"
+    android:fillViewport="true">
 
-    <com.simplemobiletools.commons.views.MyEditText
+    <com.simplemobiletools.filemanager.pro.views.GestureTextView
         android:id="@+id/read_text_view"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:background="@null"
-        android:padding="@dimen/medium_margin"
         android:inputType="textMultiLine|textNoSuggestions"
+        android:padding="@dimen/medium_margin"
         android:textCursorDrawable="@null"
         android:textSize="@dimen/smaller_text_size"/>