Created
September 27, 2025 08:46
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Scan Overlay with Camera Corner Handles and Punch Hole
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| package com.tonyxlab.qrcraft.presentation.screens.scan.components | |
| import androidx.compose.foundation.Canvas | |
| import androidx.compose.foundation.layout.Arrangement | |
| import androidx.compose.foundation.layout.Box | |
| import androidx.compose.foundation.layout.Column | |
| import androidx.compose.foundation.layout.Spacer | |
| import androidx.compose.foundation.layout.fillMaxHeight | |
| import androidx.compose.foundation.layout.fillMaxSize | |
| import androidx.compose.foundation.layout.padding | |
| import androidx.compose.foundation.layout.size | |
| import androidx.compose.material3.CircularProgressIndicator | |
| import androidx.compose.material3.MaterialTheme | |
| import androidx.compose.material3.Text | |
| import androidx.compose.runtime.Composable | |
| import androidx.compose.ui.Alignment | |
| import androidx.compose.ui.Modifier | |
| import androidx.compose.ui.geometry.CornerRadius | |
| import androidx.compose.ui.geometry.Offset | |
| import androidx.compose.ui.geometry.Size | |
| import androidx.compose.ui.graphics.BlendMode | |
| import androidx.compose.ui.graphics.Color | |
| import androidx.compose.ui.graphics.CompositingStrategy | |
| import androidx.compose.ui.graphics.Path | |
| import androidx.compose.ui.graphics.StrokeCap | |
| import androidx.compose.ui.graphics.drawscope.DrawScope | |
| import androidx.compose.ui.graphics.drawscope.Stroke | |
| import androidx.compose.ui.graphics.graphicsLayer | |
| import androidx.compose.ui.res.stringResource | |
| import androidx.compose.ui.text.style.TextAlign | |
| import androidx.compose.ui.tooling.preview.Preview | |
| import androidx.compose.ui.unit.dp | |
| import com.tonyxlab.qrcraft.R | |
| import com.tonyxlab.qrcraft.presentation.core.utils.spacing | |
| import com.tonyxlab.qrcraft.presentation.theme.ui.OnOverlay | |
| import com.tonyxlab.qrcraft.presentation.theme.ui.Overlay | |
| import com.tonyxlab.qrcraft.presentation.theme.ui.Primary | |
| import com.tonyxlab.qrcraft.presentation.theme.ui.QRCraftTheme | |
| import com.tonyxlab.qrcraft.util.Constants | |
| import kotlin.math.min | |
| @Composable | |
| fun ScanOverlay( | |
| modifier: Modifier = Modifier, | |
| isLoading: Boolean | |
| ) { | |
| val strokeWidth = MaterialTheme.spacing.spaceSmall.value | |
| Box(modifier = modifier) { | |
| Canvas( | |
| modifier = Modifier | |
| .matchParentSize() | |
| .graphicsLayer { | |
| compositingStrategy = CompositingStrategy.Offscreen | |
| } | |
| ) { | |
| val w = size.width | |
| val h = size.height | |
| // Using a constant of 0.75f | |
| val roiFraction = Constants.SCREEN_REGION_OF_INTEREST_FRACTION | |
| val sideDimen = min(w, h) * roiFraction | |
| val left = (w - sideDimen) / 2f | |
| val top = (h - sideDimen) / 2f | |
| val right = left + sideDimen | |
| val bottom = top + sideDimen | |
| val radius = 20.dp.toPx() | |
| // Draw scrim | |
| drawRect(Overlay) | |
| // Punch a transparent hole for the frame | |
| drawRoundRect( | |
| color = Color.Red, | |
| topLeft = Offset(left, top), | |
| size = Size(width = sideDimen, height = sideDimen), | |
| cornerRadius = CornerRadius(radius, radius), | |
| blendMode = BlendMode.Clear | |
| ) | |
| drawCornerGuides( | |
| left = left, | |
| top = top, | |
| right = right, | |
| bottom = bottom, | |
| strokeWidth = strokeWidth, | |
| sideDimen = sideDimen | |
| ) | |
| } | |
| // Hint Text | |
| Column( | |
| Modifier | |
| .fillMaxSize() | |
| .padding(horizontal = 24.dp), | |
| horizontalAlignment = Alignment.CenterHorizontally, | |
| verticalArrangement = Arrangement.Top | |
| ) { | |
| Spacer(Modifier.fillMaxHeight(0.25f)) | |
| Text( | |
| text = stringResource(id = R.string.cap_text_point_camera), | |
| style = MaterialTheme.typography.titleSmall.copy(color = OnOverlay), | |
| textAlign = TextAlign.Center | |
| ) | |
| } | |
| if (isLoading) { | |
| Column( | |
| modifier = Modifier.align(Alignment.Center), | |
| horizontalAlignment = Alignment.CenterHorizontally, | |
| verticalArrangement = Arrangement.spacedBy(MaterialTheme.spacing.spaceMedium) | |
| ) { | |
| CircularProgressIndicator( | |
| modifier = Modifier | |
| .size(MaterialTheme.spacing.spaceLarge) | |
| .padding(bottom = MaterialTheme.spacing.spaceMedium), | |
| color = OnOverlay | |
| ) | |
| Text( | |
| text = stringResource(id = R.string.cap_text_loading), | |
| style = MaterialTheme.typography.bodyLarge.copy( | |
| color = OnOverlay | |
| ) | |
| ) | |
| } | |
| } | |
| } | |
| } | |
| fun DrawScope.drawCornerGuides( | |
| left: Float, | |
| top: Float, | |
| right: Float, | |
| bottom: Float, | |
| strokeWidth: Float, | |
| sideDimen: Float | |
| ) { | |
| val handleLength = .2f * sideDimen | |
| val curveRadius = 40f | |
| // Draw Top-Left Corner Guide Handle | |
| drawPath( | |
| path = Path().apply { | |
| moveTo(x = left, y = top + handleLength) | |
| lineTo(x = left, y = top + curveRadius) | |
| quadraticTo(x1 = left, y1 = top, x2 = left + curveRadius, y2 = top) | |
| lineTo(x = left + handleLength, y = top) | |
| }, | |
| color = Primary, | |
| style = Stroke(width = strokeWidth, cap = StrokeCap.Round) | |
| ) | |
| // Draw Top-Right Corner Guide Handle | |
| drawPath( | |
| path = Path().apply { | |
| moveTo(x = right - handleLength, y = top) | |
| lineTo(x = right - curveRadius, y = top) | |
| quadraticTo(x1 = right, y1 = top, x2 = right, y2 = top + curveRadius) | |
| lineTo(x = right, y = top + handleLength) | |
| }, | |
| color = Primary, | |
| style = Stroke(width = strokeWidth, cap = StrokeCap.Round), | |
| ) | |
| // Draw Bottom-Left Corner Guide Handle | |
| drawPath( | |
| path = Path().apply { | |
| moveTo(x = left, y = bottom - handleLength) | |
| lineTo(x = left, y = bottom - curveRadius) | |
| quadraticTo(x1 = left, y1 = bottom, x2 = left + curveRadius, y2 = bottom) | |
| lineTo(x = left + handleLength, y = bottom) | |
| }, | |
| color = Primary, | |
| style = Stroke(width = strokeWidth, cap = StrokeCap.Round), | |
| ) | |
| // Draw Bottom-Right Corner Guide Handle | |
| drawPath( | |
| path = Path().apply { | |
| moveTo(x = right - handleLength, y = bottom) | |
| lineTo(x = right - curveRadius, y = bottom) | |
| quadraticTo(x1 = right, y1 = bottom, x2 = right, y2 = bottom - curveRadius) | |
| lineTo(x = right, y = bottom - handleLength) | |
| }, | |
| color = Primary, | |
| style = Stroke(width = strokeWidth, cap = StrokeCap.Round), | |
| ) | |
| } | |
| @Preview | |
| @Composable | |
| private fun ScanOverlay_Preview() { | |
| QRCraftTheme { | |
| ScanOverlay( | |
| modifier = Modifier.fillMaxSize(), | |
| isLoading = false | |
| ) | |
| } | |
| } |
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