android: fixed size for exported QR code (#1901)

* android: fixed size for exported QR code

* border

* automatic version

* modifier

* make image instead of screenshot

* code folding

* don't use deprecated method

* function refactor

* dropped unneeded variable

apps/android/app/src/main/java/chat/simplex/app/views/newchat/QRCode.kt

@@ -3,80 +3,73 @@ package chat.simplex.app.views.newchat
 import android.graphics.Bitmap
 import androidx.compose.foundation.*
 import androidx.compose.foundation.layout.*
-import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.runtime.*
-import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.geometry.Rect
 import androidx.compose.ui.graphics.*
-import androidx.compose.ui.layout.boundsInRoot
-import androidx.compose.ui.layout.onGloballyPositioned
-import androidx.compose.ui.platform.LocalContext
-import androidx.compose.ui.platform.LocalView
-import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.platform.*
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.tooling.preview.Preview
-import androidx.core.graphics.applyCanvas
+import androidx.core.graphics.*
+import androidx.core.graphics.drawable.toBitmap
+import boofcv.alg.drawing.FiducialImageEngine
 import boofcv.alg.fiducial.qrcode.*
 import boofcv.android.ConvertBitmap
 import chat.simplex.app.R
+import chat.simplex.app.SimplexApp
 import chat.simplex.app.ui.theme.SimpleXTheme
 import chat.simplex.app.views.helpers.*
 import kotlinx.coroutines.launch
 
 @Composable
-fun QRCode(connReq: String, modifier: Modifier = Modifier, withLogo: Boolean = true, tintColor: Color = Color(0xff062d56)) {
-  val view = LocalView.current
+fun QRCode(
+  connReq: String,
+  modifier: Modifier = Modifier,
+  tintColor: Color = Color(0xff062d56),
+  withLogo: Boolean = true
+) {
   val context = LocalContext.current
   val scope = rememberCoroutineScope()
-  var rect by remember { mutableStateOf<Rect?>(null) }
-  BoxWithConstraints(Modifier
-    .onGloballyPositioned {
-      rect = it.boundsInRoot()
+
+  BoxWithConstraints {
+    val maxWidthInPx = with(LocalDensity.current) { maxWidth.roundToPx() }
+    val qr = remember(maxWidthInPx, connReq, tintColor, withLogo) {
+      qrCodeBitmap(connReq, maxWidthInPx).replaceColor(Color.Black.toArgb(), tintColor.toArgb())
+        .let { if (withLogo) it.addLogo() else it }
+        .asImageBitmap()
     }
-    .clickable {
-      scope.launch {
-        val r = rect
-        if (r != null) {
-          val image = Bitmap.createBitmap(r.width.toInt(), r.height.toInt(), Bitmap.Config.ARGB_8888).applyCanvas {
-            translate(-r.left, -r.top)
-            view.draw(this)
-          }
-          val file = saveTempImageUncompressed(image, false)
-          if (file != null) {
-            shareFile(context, "", file.absolutePath)
+    Image(
+      bitmap = qr,
+      contentDescription = stringResource(R.string.image_descr_qr_code),
+      modifier
+        .clickable {
+          scope.launch {
+            val image = qrCodeBitmap(connReq, 1024).replaceColor(Color.Black.toArgb(), tintColor.toArgb())
+              .let { if (withLogo) it.addLogo() else it }
+            val file = saveTempImageUncompressed(image, false)
+            if (file != null) {
+              shareFile(context, "", file.absolutePath)
+            }
           }
         }
-      }
-    },
-    contentAlignment = Alignment.Center
-  ) {
-    Image(
-      bitmap = qrCodeBitmap(connReq, 1024).replaceColor(Color.Black.toArgb(), tintColor.toArgb()).asImageBitmap(),
-      contentDescription = stringResource(R.string.image_descr_qr_code),
-      modifier = modifier
     )
-    if (withLogo) {
-      Box(
-        Modifier
-          .size(maxWidth * 0.16f)
-          .background(Color.White, RoundedCornerShape(100))
-      )
-      Image(
-        painterResource(R.mipmap.icon_foreground),
-        null,
-        Modifier
-          .size(maxWidth * 0.24f)
-      )
-    }
   }
 }
 
-fun qrCodeBitmap(content: String, size: Int): Bitmap {
+fun qrCodeBitmap(content: String, size: Int = 1024): Bitmap {
   val qrCode = QrCodeEncoder().addAutomatic(content).setError(QrCode.ErrorLevel.L).fixate()
-  val renderer = QrCodeGeneratorImage(5)
+  /** See [QrCodeGeneratorImage.initialize] and [FiducialImageEngine.configure] for size calculation */
+  val numModules = QrCode.totalModules(qrCode.version)
+  val borderModule = 1
+  // val calculatedFinalWidth = (pixelsPerModule * numModules) + 2 * (borderModule * pixelsPerModule)
+  // size = (x * numModules) + 2 * (borderModule * x)
+  // size / x = numModules + 2 * borderModule
+  // x = size / (numModules + 2 * borderModule)
+  val pixelsPerModule = size / (numModules + 2 * borderModule)
+  // + 1 to make it with better quality
+  val renderer = QrCodeGeneratorImage(pixelsPerModule + 1)
+  renderer.borderModule = borderModule
   renderer.render(qrCode)
-  return ConvertBitmap.grayToBitmap(renderer.gray, Bitmap.Config.RGB_565)
+  return ConvertBitmap.grayToBitmap(renderer.gray, Bitmap.Config.RGB_565).scale(size, size)
 }
 
 fun Bitmap.replaceColor(from: Int, to: Int): Bitmap {
@@ -93,6 +86,17 @@ fun Bitmap.replaceColor(from: Int, to: Int): Bitmap {
   return this
 }
 
+fun Bitmap.addLogo(): Bitmap = applyCanvas {
+  val radius = (width * 0.16f) / 2
+  val paint = android.graphics.Paint()
+  paint.color = android.graphics.Color.WHITE
+  drawCircle(width / 2f, height / 2f, radius, paint)
+  val logo = SimplexApp.context.resources.getDrawable(R.mipmap.icon_foreground, null).toBitmap()
+  val logoSize = (width * 0.24).toInt()
+  translate((width - logoSize) / 2f, (height - logoSize) / 2f)
+  drawBitmap(logo, null, android.graphics.Rect(0, 0, logoSize, logoSize), null)
+}
+
 @Preview
 @Composable
 fun PreviewQRCode() {