feat(ecl-auto): Fixes and new example

Author: rafaellins-swile

examples/kotlin/example01-circles.png

@@ -0,0 +1,28 @@
+import qrcode.QRCode
+import qrcode.raw.MaskPattern
+import java.io.FileOutputStream
+
+fun main() {
+    // This example shows that the same data can be encoded with many different patterns.
+    // The default (000) is no pattern at all :)
+    // As far as I know, this is only for aesthetics.
+    // For more info: https://www.thonky.com/qr-code-tutorial/mask-patterns (accessed 03/2025)
+
+    // All supported platforms
+    // -----------------------
+    MaskPattern.entries.forEachIndexed { index, entry ->
+        val number = index.toString(2).padStart(3, '0')
+        qrcodeForMaskPattern(number, entry)
+    }
+}
+
+private fun qrcodeForMaskPattern(number: String, maskPattern: MaskPattern) {
+    val qrCodeData = "Hello, Mask Pattern."
+
+    val maskPatternQRCode = QRCode.ofSquares()
+        .withMaskPattern(maskPattern)
+        .build(qrCodeData)
+    val maskPatternPngData = maskPatternQRCode.renderToBytes()
+
+    FileOutputStream("examples/kotlin/example07-mask-pattern-$number.png").use { it.write(maskPatternPngData) }
+}

examples/kotlin/example01-custom-jvm.png

@@ -1,6 +1,7 @@
 import qrcode.QRCode
 import qrcode.color.Colors
 import qrcode.color.Colors.css
+import qrcode.raw.ErrorCorrectionLevel
 import java.awt.Color
 import java.awt.MultipleGradientPaint.CycleMethod.NO_CYCLE
 import java.awt.RadialGradientPaint
@@ -17,6 +18,8 @@ fun main() {
         .withColor(Colors.rgba(255, 255, 255, 180))
         .withBackgroundColor(Colors.TRANSPARENT)
         .withLogo(logoBytes, 150, 150)
+        .withInformationDensity(6)
+        .withErrorCorrectionLevel(ErrorCorrectionLevel.VERY_HIGH)
         .build("https://qrcodekotlin.com")
 
     // Before drawing the QRCode, draw our gradient as the background

examples/kotlin/example01-custom.png

@@ -328,7 +328,10 @@ class QRCodeBuilder @JvmOverloads constructor(
             shapeFunction,
             graphicsFactory,
             errorCorrectionLevel,
-            informationDensity,
+            when (informationDensity) {
+                0 -> QRCodeProcessor.infoDensityForDataAndECL(data, errorCorrectionLevel)
+                else -> informationDensity
+            },
             maskPattern,
             beforeFn,
             afterFn,

examples/kotlin/example01-rounded-squares.png

@@ -1,11 +1,10 @@
 package qrcode.exception
 
+/**
+ * Thrown when the Information Density parameter is not enough to hold all the data that needs to be encoded in the
+ * QRCode.
+ */
 class InsufficientInformationDensityException(
-    val informationDensity: Int,
-    val neededBytes: Int,
-    val maximumBytesSupported: Int,
+    override val message: String? = null,
     override val cause: Throwable? = null,
-) : IllegalArgumentException(
-    message = "Insufficient Information Density Parameter: $informationDensity [neededBytes=$neededBytes, maximumBytesSupported=$maximumBytesSupported] - Try increasing the parameter value or use 0 (zero) to automatically compute the least amount needed to fit the QRCode data being encoded.",
-    cause,
-)
+) : IllegalArgumentException(message, cause)

examples/kotlin/example01-squares.png

@@ -25,6 +25,7 @@ import qrcode.internals.RSBlock
 import qrcode.raw.QRCodeDataType.DEFAULT
 import qrcode.raw.QRCodeDataType.NUMBERS
 import qrcode.raw.QRCodeDataType.UPPER_ALPHA_NUM
+import qrcode.raw.QRCodeProcessor.Companion.MAXIMUM_INFO_DENSITY
 import qrcode.raw.QRCodeProcessor.Companion.infoDensityForDataAndECL
 import qrcode.render.QRCodeGraphics
 import qrcode.render.QRCodeGraphicsFactory
@@ -365,7 +366,8 @@ class QRCodeProcessor @JvmOverloads constructor(
         val totalDataCount = rsBlocks.sumOf { it.dataCount } * 8
 
         if (buffer.lengthInBits > totalDataCount) {
-            throw InsufficientInformationDensityException(type, buffer.lengthInBits, totalDataCount)
+            val errorMessage = "Insufficient Information Density Parameter: $type [neededBits=${buffer.lengthInBits}, maximumBitsForDensityLevel=$totalDataCount] - Try increasing the Information Density parameter value or use 0 (zero) to automatically compute the least amount needed to fit the QRCode data being encoded."
+            throw InsufficientInformationDensityException(errorMessage)
         }
 
         if (buffer.lengthInBits + 4 <= totalDataCount) {