add alignment to image in Tutorial5_15ImageBoundsRect

Author: SmartToolFactory

Tutorial1-1Basics/src/main/java/com/smarttoolfactory/tutorial1_1basics/chapter5_gesture/Tutorial5_15ImageBoundsRect.kt

@@ -27,6 +27,7 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.runtime.snapshots.SnapshotStateList
 import androidx.compose.ui.Alignment
+import androidx.compose.ui.BiasAlignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.drawWithContent
 import androidx.compose.ui.geometry.Offset
@@ -49,15 +50,41 @@ import com.smarttoolfactory.tutorial1_1basics.R
 import java.util.UUID
 
 
-private fun calculateRect(srcSize: Size, dstSize: Size, contentScale: ContentScale): Rect {
+private fun calculateRect(
+ srcSize: Size,
+ dstSize: Size,
+ contentScale: ContentScale,
+ alignment: Alignment
+): Rect {
  val scaleFactor = contentScale.computeScaleFactor(srcSize, dstSize)
 
  val scaledSrcSize = Size(
  srcSize.width * scaleFactor.scaleX,
  srcSize.height * scaleFactor.scaleY
  )
- val left = ((dstSize.width - scaledSrcSize.width) / 2).coerceAtLeast(0f)
- val top = ((dstSize.height - scaledSrcSize.height) / 2).coerceAtLeast(0f)
+
+ val biasAlignment: BiasAlignment = alignment as BiasAlignment
+
+ // - Left, 0 Center, 1 Right
+ val horizontalBias: Float = biasAlignment.horizontalBias
+ // -1 Top, 0 Center, 1 Bottom
+ val verticalBias: Float = biasAlignment.verticalBias
+
+
+ val horizontalGap = ((dstSize.width - scaledSrcSize.width) / 2).coerceAtLeast(0f)
+ val verticalGap = ((dstSize.height - scaledSrcSize.height) / 2).coerceAtLeast(0f)
+
+ val left = when (horizontalBias) {
+ -1f -> 0f
+ 0f -> horizontalGap
+ else -> horizontalGap * 2
+ }
+
+ val top = when (verticalBias) {
+ -1f -> 0f
+ 0f -> verticalGap
+ else -> verticalGap * 2
+ }
 
  val right = (left + scaledSrcSize.width).coerceAtMost(dstSize.width)
  val bottom = (top + scaledSrcSize.height).coerceAtMost(dstSize.height)
@@ -77,7 +104,7 @@ data class ImgAnnotation(
 @Preview
 @Composable
 fun ImageWithMarkersSample() {
- val imageBitmap: ImageBitmap = ImageBitmap.imageResource(R.drawable.landscape3)
+ val imageBitmap: ImageBitmap = ImageBitmap.imageResource(R.drawable.landscape11)
 
  val imgAnnotationList = remember {
  mutableStateListOf<ImgAnnotation>()
@@ -168,6 +195,7 @@ fun ImageWithMarkersSample() {
  .fillMaxWidth()
  .aspectRatio(5 / 3f),
  contentScale = ContentScale.Fit,
+ alignment = Alignment.BottomEnd,
  imgAnnotationList = imgAnnotationList,
  imageBitmap = imageBitmap
  ) {
@@ -185,6 +213,7 @@ fun ImageWithMarkersSample() {
 private fun ImageWithMarkers(
  modifier: Modifier = Modifier,
  contentScale: ContentScale,
+ alignment: Alignment = Alignment.Center,
  imgAnnotationList: SnapshotStateList<ImgAnnotation>,
  imageBitmap: ImageBitmap,
  onClick: (ImgAnnotation) -> Unit
@@ -236,7 +265,7 @@ private fun ImageWithMarkers(
  val srcSize =
  Size(imageBitmap.width.toFloat(), imageBitmap.height.toFloat())
 
- rect = calculateRect(srcSize, dstSize, contentScale)
+ rect = calculateRect(srcSize, dstSize, contentScale, alignment)
 
  val rectWidth = rect.width
  val rectHeight = rect.height
@@ -246,6 +275,7 @@ private fun ImageWithMarkers(
  },
  bitmap = imageBitmap,
  contentScale = contentScale,
+ alignment = alignment,
  contentDescription = null
  )