1 files changed, 147 insertions, 0 deletions
diff --git a/library/src/main/kotlin/ca/allanwang/kau/views/KauCutoutTextView.kt b/library/src/main/kotlin/ca/allanwang/kau/views/KauCutoutTextView.kt
new file mode 100644
index 0000000..8df604a
--- /dev/null
+++ b/library/src/main/kotlin/ca/allanwang/kau/views/KauCutoutTextView.kt
@@ -0,0 +1,147 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ca.allanwang.kau.views
+
+import android.content.Context
+import android.graphics.*
+import android.text.TextPaint
+import android.util.AttributeSet
+import android.util.DisplayMetrics
+import android.util.TypedValue
+import android.view.View
+import ca.allanwang.kau.R
+import ca.allanwang.kau.logging.KL
+import ca.allanwang.kau.utils.dimenPixelSize
+import ca.allanwang.kau.utils.getFont
+import ca.allanwang.kau.utils.parentVisibleHeight
+
+/**
+ * A view which punches out some text from an opaque color block, allowing you to see through it.
+ */
+class KauCutoutTextView @JvmOverloads constructor(
+        context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
+) : View(context, attrs, defStyleAttr) {
+    private val textPaint: TextPaint = TextPaint(Paint.ANTI_ALIAS_FLAG)
+    private var cutout: Bitmap? = null
+    var foregroundColor = Color.MAGENTA
+    var text: String? = "Text"
+    var overlayType: Int = 0 //todo add vector overlay options
+    private var textSize: Float = 0f
+    private var textY: Float = 0f
+    private var textX: Float = 0f
+    private var heightPercentage: Float = 0f
+    private var minHeight: Float = 0f
+    private val maxTextSize: Float
+
+    init {
+        if (attrs != null) {
+            val a = context.obtainStyledAttributes(attrs, R.styleable.KauCutoutTextView, 0, 0)
+            if (a.hasValue(R.styleable.KauCutoutTextView_kau_font))
+                textPaint.typeface = context.getFont(a.getString(R.styleable.KauCutoutTextView_kau_font))
+            foregroundColor = a.getColor(R.styleable.KauCutoutTextView_kau_foregroundColor, foregroundColor)
+            text = a.getString(R.styleable.KauCutoutTextView_android_text) ?: text
+            minHeight = a.getDimension(R.styleable.KauCutoutTextView_android_minHeight, minHeight)
+            heightPercentage = a.getFloat(R.styleable.KauCutoutTextView_kau_heightPercentageToScreen, heightPercentage)
+            a.recycle()
+        }
+        maxTextSize = context.dimenPixelSize(R.dimen.kau_display_4_text_size).toFloat()
+    }
+
+    override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
+        super.onSizeChanged(w, h, oldw, oldh)
+        calculateTextPosition()
+        createBitmap()
+        KL.d("Size changed")
+    }
+
+    private fun calculateTextPosition() {
+        val targetWidth = width / PHI
+        textSize = getSingleLineTextSize(text!!, textPaint, targetWidth, 0f, maxTextSize,
+                0.5f, resources.displayMetrics)
+        textPaint.textSize = textSize
+
+        // measuring text is fun :] see: https://chris.banes.me/2014/03/27/measuring-text/
+        textX = (width - textPaint.measureText(text)) / 2
+        val textBounds = Rect()
+        textPaint.getTextBounds(text, 0, text!!.length, textBounds)
+        val textHeight = textBounds.height().toFloat()
+        textY = (height + textHeight) / 2
+    }
+
+    /**
+     * If height percent is specified, ensure it is met
+     */
+    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
+        val minHeight = Math.max(minHeight, heightPercentage * parentVisibleHeight)
+        val trueHeightMeasureSpec = if (minHeight > 0)
+            MeasureSpec.makeMeasureSpec(Math.max(minHeight.toInt(), measuredHeight), MeasureSpec.EXACTLY)
+        else heightMeasureSpec
+        super.onMeasure(widthMeasureSpec, trueHeightMeasureSpec)
+    }
+
+    /**
+     * Recursive binary search to find the best size for the text.
+
+     * Adapted from https://github.com/grantland/android-autofittextview
+     */
+    fun getSingleLineTextSize(text: String,
+                              paint: TextPaint,
+                              targetWidth: Float,
+                              low: Float,
+                              high: Float,
+                              precision: Float,
+                              metrics: DisplayMetrics): Float {
+        val mid = (low + high) / 2.0f
+
+        paint.textSize = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, mid, metrics)
+        val maxLineWidth = paint.measureText(text)
+
+        if (high - low < precision) {
+            return low
+        } else if (maxLineWidth > targetWidth) {
+            return getSingleLineTextSize(text, paint, targetWidth, low, mid, precision, metrics)
+        } else if (maxLineWidth < targetWidth) {
+            return getSingleLineTextSize(text, paint, targetWidth, mid, high, precision, metrics)
+        } else {
+            return mid
+        }
+    }
+
+    private fun createBitmap() {
+        if (!(cutout?.isRecycled ?: true))
+            cutout?.recycle()
+        if (width == 0 || height == 0) return
+        cutout = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888)
+        cutout!!.setHasAlpha(true)
+        val cutoutCanvas = Canvas(cutout!!)
+        cutoutCanvas.drawColor(foregroundColor)
+
+        // this is the magic – Clear mode punches out the bitmap
+        textPaint.xfermode = PorterDuffXfermode(PorterDuff.Mode.CLEAR)
+        cutoutCanvas.drawText(text, textX, textY, textPaint)
+    }
+
+    override fun onDraw(canvas: Canvas) {
+        canvas.drawBitmap(cutout!!, 0f, 0f, null)
+    }
+
+    override fun hasOverlappingRendering(): Boolean = true
+
+    companion object {
+        val PHI = 1.6182f
+    }
+}