Add image composition and text overlay functionality

app/src/main/java/com/example/app/CameraActivity.kt

@@ -18,9 +18,7 @@ import android.os.Bundle
 import android.os.Looper
 import android.provider.MediaStore
 import android.util.Log
-import android.widget.ImageButton
+import android.widget.*
-import android.widget.LinearLayout
-import android.widget.Toast
 import androidx.appcompat.app.AppCompatActivity
 import androidx.camera.core.CameraSelector
 import androidx.camera.core.ImageCapture
@@ -31,11 +29,11 @@ import androidx.camera.view.PreviewView
 import androidx.core.app.ActivityCompat
 import androidx.core.content.ContextCompat
 import com.google.android.material.snackbar.Snackbar
+import java.io.ByteArrayOutputStream
 import java.io.IOException
 import java.io.OutputStream
 import java.text.SimpleDateFormat
-import java.util.Date
+import java.util.*
-import java.util.Locale
 import java.util.concurrent.ExecutorService
 import java.util.concurrent.Executors
 import kotlin.math.roundToInt
@@ -58,6 +56,11 @@ class CameraActivity : AppCompatActivity() {
     private var imageCapture: ImageCapture? = null
     private lateinit var cameraExecutor: ExecutorService
     
+    // 存储拍摄的图片URI
+    private val capturedImageUris = mutableListOf<Uri>()
+    // 图片合成器
+    private val compositor = ImageCompositor()
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
@@ -140,10 +143,18 @@ class CameraActivity : AppCompatActivity() {
                 }
 
                 override fun onImageSaved(output: ImageCapture.OutputFileResults) {
-                    // 添加水印到已保存的照片
+                    // 获取保存的URI
                     val savedUri = output.savedUri ?: return
+                    
+                    // 添加水印到已保存的照片
                     addWatermarkToImage(savedUri)
                     
+                    // 添加到捕获的图片列表
+                    capturedImageUris.add(savedUri)
+                    
+                    // 更新预览
+                    updatePhotoPreviews()
+                    
                     Toast.makeText(
                         baseContext, 
                         "照片已保存", 
@@ -215,6 +226,142 @@ class CameraActivity : AppCompatActivity() {
         return watermarkedBitmap
     }
 
+    private fun updatePhotoPreviews() {
+        // 清空当前预览
+        photoPreviewLayout.removeAllViews()
+        
+        // 限制最多显示4张预览图
+        val displayCount = minOf(capturedImageUris.size, 4)
+        
+        for (i in 0 until displayCount) {
+            val imageView = ImageView(this)
+            val params = LinearLayout.LayoutParams(
+                200, 200
+            ).apply {
+                setMargins(8, 8, 8, 8)
+            }
+            imageView.layoutParams = params
+            imageView.scaleType = ImageView.ScaleType.CENTER_CROP
+            
+            // 加载并设置图片
+            val uri = capturedImageUris[capturedImageUris.size - displayCount + i] // 显示最新的几张
+            imageView.setImageURI(uri)
+            
+            // 添加点击事件以查看大图
+            imageView.setOnClickListener {
+                // 可以在这里实现查看大图的功能
+            }
+            
+            photoPreviewLayout.addView(imageView)
+        }
+        
+        // 如果已有4张图片，添加合成按钮
+        if (capturedImageUris.size >= 4) {
+            addComposeButton()
+        }
+    }
+
+    private fun addComposeButton() {
+        // 添加合成按钮
+        val composeButton = Button(this)
+        composeButton.text = "合成图片"
+        composeButton.setBackgroundColor(ContextCompat.getColor(this, R.color.purple_200))
+        composeButton.setTextColor(Color.WHITE)
+        
+        val params = LinearLayout.LayoutParams(
+            LinearLayout.LayoutParams.WRAP_CONTENT,
+            LinearLayout.LayoutParams.WRAP_CONTENT
+        ).apply {
+            setMargins(8, 8, 8, 8)
+            gravity = android.view.Gravity.CENTER_HORIZONTAL
+        }
+        composeButton.layoutParams = params
+        
+        composeButton.setOnClickListener {
+            composeLastFourImages()
+        }
+        
+        photoPreviewLayout.addView(composeButton)
+    }
+
+    private fun composeLastFourImages() {
+        // 获取最近的4张图片
+        val recentUris = if (capturedImageUris.size >= 4) {
+            capturedImageUris.takeLast(4)
+        } else {
+            capturedImageUris
+        }
+        
+        // 将URI转换为Bitmap
+        val bitmaps = mutableListOf<Bitmap>()
+        for (uri in recentUris) {
+            try {
+                val inputStream = contentResolver.openInputStream(uri)
+                val bitmap = BitmapFactory.decodeStream(inputStream)
+                inputStream?.close()
+                bitmaps.add(bitmap)
+            } catch (e: Exception) {
+                Log.e(TAG, "加载图片失败: ${e.message}")
+            }
+        }
+        
+        if (bitmaps.isEmpty()) {
+            Toast.makeText(this, "没有图片可合成", Toast.LENGTH_SHORT).show()
+            return
+        }
+        
+        // 合成图片
+        val composedBitmap = compositor.composeImagesToGrid(bitmaps, 2000, 2000) // 目标尺寸2000x2000
+        
+        // 添加标题和内容
+        val finalBitmap = compositor.addTextOverlay(
+            composedBitmap,
+            "巡检报告", 
+            "这是巡检内容的详细描述"
+        )
+        
+        // 保存合成后的图片
+        saveCompositedImage(finalBitmap)
+        
+        // 回收位图
+        for (bitmap in bitmaps) {
+            if (bitmap != finalBitmap) {
+                bitmap.recycle()
+            }
+        }
+        if (finalBitmap != composedBitmap) {
+            composedBitmap.recycle()
+        }
+    }
+
+    private fun saveCompositedImage(bitmap: Bitmap) {
+        try {
+            val fileName = compositor.generateFileName()
+            val contentValues = ContentValues().apply {
+                put(MediaStore.Images.Media.DISPLAY_NAME, fileName)
+                put(MediaStore.Images.Media.MIME_TYPE, "image/jpeg")
+                if (Build.VERSION.SDK_INT > Build.VERSION_CODES.P) {
+                    put(MediaStore.Images.Media.DATE_TAKEN, System.currentTimeMillis())
+                }
+            }
+            
+            val uri = contentResolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, contentValues)
+                ?: throw IOException("无法创建图片URI")
+            
+            val outputStream = contentResolver.openOutputStream(uri)
+            bitmap.compress(Bitmap.CompressFormat.JPEG, 95, outputStream)
+            outputStream?.close()
+            
+            Toast.makeText(this, "合成图片已保存", Toast.LENGTH_SHORT).show()
+            
+            // 刷新相册
+            refreshGallery(uri)
+        } catch (e: Exception) {
+            Log.e(TAG, "保存合成图片失败: ${e.message}")
+            Toast.makeText(this, "保存合成图片失败", Toast.LENGTH_SHORT).show()
+        }
+    }
+
     private fun refreshGallery(uri: Uri) {
         // 通知相册更新
         val contentValues = ContentValues().apply {

app/src/main/java/com/example/app/ImageCompositor.kt

@@ -0,0 +1,145 @@
+package com.example.app
+
+import android.graphics.*
+import java.io.File
+import java.text.SimpleDateFormat
+import java.util.*
+
+class ImageCompositor {
+    
+    /**
+     * 将多张图片合成到2x2网格布局中
+     */
+    fun composeImagesToGrid(images: List<Bitmap>, targetWidth: Int, targetHeight: Int): Bitmap {
+        // 创建目标位图
+        val composedBitmap = Bitmap.createBitmap(targetWidth, targetHeight, Bitmap.Config.ARGB_8888)
+        val canvas = Canvas(composedBitmap)
+        canvas.drawColor(Color.WHITE) // 白色背景
+        
+        // 计算每个网格的尺寸
+        val cellWidth = targetWidth / 2
+        val cellHeight = targetHeight / 2
+        
+        // 绘制每张图片到对应网格
+        for ((index, bitmap) in images.withIndex()) {
+            if (index >= 4) break // 最多4张图片
+            
+            val row = index / 2
+            val col = index % 2
+            
+            // 计算目标矩形
+            val dstRect = Rect(col * cellWidth, row * cellHeight, 
+                              (col + 1) * cellWidth, (row + 1) * cellHeight)
+            
+            // 缩放图片以适应网格
+            val scaledBitmap = Bitmap.createScaledBitmap(bitmap, cellWidth, cellHeight, true)
+            
+            // 绘制到画布
+            canvas.drawBitmap(scaledBitmap, null, dstRect, null)
+            
+            // 回收临时位图
+            if (scaledBitmap != bitmap) {
+                scaledBitmap.recycle()
+            }
+        }
+        
+        return composedBitmap
+    }
+    
+    /**
+     * 在图片上添加标题和内容文字
+     */
+    fun addTextOverlay(bitmap: Bitmap, title: String?, content: String?): Bitmap {
+        val resultBitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true)
+        val canvas = Canvas(resultBitmap)
+        
+        // 文字样式配置
+        val titlePaint = Paint().apply {
+            color = Color.BLACK
+            textSize = 48f
+            typeface = Typeface.DEFAULT_BOLD
+            textAlign = Paint.Align.CENTER
+        }
+        
+        val contentPaint = Paint().apply {
+            color = Color.BLACK
+            textSize = 36f
+            typeface = Typeface.DEFAULT
+            textAlign = Paint.Align.CENTER
+        }
+        
+        val bgColor = Color.argb(180, 255, 255, 255) // 半透明白色背景
+        
+        // 绘制标题（顶部）
+        if (!title.isNullOrBlank()) {
+            // 计算标题背景矩形
+            val titleBgHeight = 100
+            val titleBgRect = Rect(0, 0, resultBitmap.width, titleBgHeight)
+            val bgPaint = Paint().apply { color = bgColor }
+            canvas.drawRect(titleBgRect, bgPaint)
+            
+            // 绘制标题文字（居中）
+            val titleX = resultBitmap.width / 2f
+            val titleY = titleBgHeight / 2f - (titlePaint.fontMetrics.ascent + titlePaint.fontMetrics.descent) / 2
+            canvas.drawText(title, titleX, titleY, titlePaint)
+        }
+        
+        // 绘制内容（底部）
+        if (!content.isNullOrBlank()) {
+            // 计算内容背景矩形
+            val contentBgHeight = 200
+            val contentBgRect = Rect(0, resultBitmap.height - contentBgHeight, 
+                                   resultBitmap.width, resultBitmap.height)
+            val bgPaint = Paint().apply { color = bgColor }
+            canvas.drawRect(contentBgRect, bgPaint)
+            
+            // 绘制内容文字（多行处理）
+            val contentX = resultBitmap.width / 2f
+            val contentY = resultBitmap.height - contentBgHeight / 2f
+            drawMultilineText(canvas, content, contentX, contentY, contentPaint, contentBgHeight)
+        }
+        
+        return resultBitmap
+    }
+    
+    /**
+     * 绘制多行文字
+     */
+    private fun drawMultilineText(
+        canvas: Canvas, 
+        text: String, 
+        centerX: Float, 
+        centerY: Float, 
+        paint: Paint, 
+        maxHeight: Int
+    ) {
+        val staticLayout = StaticLayout.Builder
+            .obtain(text, 0, text.length, 
+                    paint, (canvas.width * 0.9).toInt())
+            .setMaxLines(5) // 限制最大行数
+            .setAlignment(Layout.Alignment.ALIGN_CENTER)
+            .build()
+        
+        // 计算垂直居中的起始Y位置
+        val totalHeight = staticLayout.height
+        val startY = if (totalHeight <= maxHeight) {
+            centerY - totalHeight / 2
+        } else {
+            (canvas.height - maxHeight).toFloat()
+        }
+        
+        canvas.save()
+        canvas.translate(centerX - staticLayout.width / 2, startY)
+        staticLayout.draw(canvas)
+        canvas.restore()
+    }
+    
+    /**
+     * 生成带时间戳的文件名
+     */
+    fun generateFileName(subject: String = "巡检报告"): String {
+        val dateFormat = SimpleDateFormat("yyyyMMddHHmm", Locale.getDefault())
+        val currentTime = dateFormat.format(Date())
+        return "${subject}_${currentTime}.jpg"
+    }
+}