add map image converter

Signed-off-by: Peter Siegmund <peter@rdkr.com>

backend/pom.xml

@@ -32,6 +32,10 @@
 			<groupId>org.springframework.modulith</groupId>
 			<artifactId>spring-modulith-starter-core</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-cache</artifactId>
+		</dependency>
 
 		<dependency>
 			<groupId>org.springframework.boot</groupId>

backend/src/main/java/com/rdkr/tide_display/backend/common/CacheConfig.java

@@ -0,0 +1,17 @@
+package com.rdkr.tide_display.backend.common;
+
+import org.springframework.cache.CacheManager;
+import org.springframework.cache.annotation.EnableCaching;
+import org.springframework.cache.concurrent.ConcurrentMapCacheManager;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+@EnableCaching
+public class CacheConfig {
+
+  @Bean
+  public CacheManager cacheManager() {
+    return new ConcurrentMapCacheManager("map", "grayMap", "ePaper", "printHexValues");
+  }
+}

backend/src/main/java/com/rdkr/tide_display/backend/images/controller/MapController.java

@@ -0,0 +1,43 @@
+package com.rdkr.tide_display.backend.images.controller;
+
+import com.rdkr.tide_display.backend.images.domain.ImageFormat;
+import com.rdkr.tide_display.backend.images.services.ImageConverterService;
+import com.rdkr.tide_display.backend.images.services.MapService;
+import java.io.IOException;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import lombok.val;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/map")
+@RequiredArgsConstructor
+@Slf4j
+public class MapController {
+
+  private final MapService mapService;
+  private final ImageConverterService converterService;
+
+  @GetMapping
+  public ResponseEntity<?> getMap(
+      @RequestParam(required = false, defaultValue = "53.541962") double latitude,
+      @RequestParam(required = false, defaultValue = "9.993402") double longitude,
+      @RequestParam(required = false, defaultValue = "15") int zoom,
+      @RequestParam(required = false, defaultValue = "BINARY") ImageFormat format)
+      throws IOException {
+    val map = mapService.getStaticMap(latitude, longitude, zoom);
+    var result = converterService.grayscale(map);
+    val response = ResponseEntity.ok();
+    if (ImageFormat.PNG.equals(format)) {
+      return response.contentType(MediaType.IMAGE_PNG).body(result);
+    } else {
+      val body = converterService.ePaperFormat(result);
+      return response.contentType(MediaType.APPLICATION_JSON).body(body);
+    }
+  }
+}

backend/src/main/java/com/rdkr/tide_display/backend/images/domain/ImageFormat.java

@@ -0,0 +1,6 @@
+package com.rdkr.tide_display.backend.images.domain;
+
+public enum ImageFormat {
+  PNG,
+  BINARY
+}

backend/src/main/java/com/rdkr/tide_display/backend/images/responses/ImageResponse.java

@@ -0,0 +1,5 @@
+package com.rdkr.tide_display.backend.images.responses;
+
+public record ImageResponse(int width, int height, byte[] data) {
+
+}

backend/src/main/java/com/rdkr/tide_display/backend/images/services/ImageConverterService.java

@@ -0,0 +1,84 @@
+package com.rdkr.tide_display.backend.images.services;
+
+import com.rdkr.tide_display.backend.images.responses.ImageResponse;
+import java.awt.image.BufferedImage;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.Base64;
+import java.util.HexFormat;
+import javax.imageio.ImageIO;
+import lombok.extern.slf4j.Slf4j;
+import lombok.val;
+import org.springframework.stereotype.Service;
+
+@Service
+@Slf4j
+public class ImageConverterService {
+
+  public byte[] grayscale(byte[] image) throws IOException {
+    return grayscale_manual(image);
+  }
+
+  public byte[] grayscale_automatic(byte[] image) throws IOException {
+    val img = ImageIO.read(new ByteArrayInputStream(image));
+    val grayImage = new BufferedImage(img.getWidth(), img.getHeight(), BufferedImage.TYPE_BYTE_GRAY);
+    val g = grayImage.getGraphics();
+    g.drawImage(img, 0, 0, null);
+    g.dispose();
+    val out = new ByteArrayOutputStream();
+    ImageIO.write(grayImage, "png", out);
+    return out.toByteArray();
+  }
+
+  public byte[] grayscale_manual(byte[] image) throws IOException {
+    val img = ImageIO.read(new ByteArrayInputStream(image));
+    val grayImage = new BufferedImage(img.getWidth(), img.getHeight(), BufferedImage.TYPE_BYTE_GRAY);
+    int rgb = 0, r = 0, g = 0, b = 0;
+    for (int y = 0; y < img.getHeight(); y++) {
+      for (int x = 0; x < img.getWidth(); x++) {
+        rgb = img.getRGB(x, y);
+        r = (rgb >> 16) & 0xFF;
+        g = (rgb >> 8) & 0xFF;
+        b = (rgb & 0xFF);
+        rgb = (int) (r * 0.299 + g * 0.587 + b * 0.114);
+        rgb = (255 << 24) | (rgb << 16) | (rgb << 8) | rgb;
+        grayImage.setRGB(x, y, rgb);
+      }
+    }
+    val out = new ByteArrayOutputStream();
+    ImageIO.write(grayImage, "png", out);
+    return out.toByteArray();
+  }
+
+  public ImageResponse ePaperFormat(byte[] image) throws IOException {
+    val img = ImageIO.read(new ByteArrayInputStream(image));
+    val width = img.getWidth();
+    val height = img.getHeight();
+    val result = new ByteArrayOutputStream(image.length);
+    for (int y = 0; y < height; y++) {
+      int b = 0;
+      boolean done = true;
+      for (int x = 0; x < width; x++) {
+        val color = img.getRGB(x, y);
+        if (x % 2 == 0) {
+          b = color >> 4;
+          done = false;
+        } else {
+          b |= color & 0xF0;
+          result.write(b);
+          done = true;
+        }
+      }
+      if (!done) {
+        result.write(b);
+      }
+    }
+    return new ImageResponse(width, height, Base64.getEncoder().encode(result.toByteArray()));
+  }
+
+  public void printHexValues(byte[] bytes) throws IOException {
+    val hex = HexFormat.of().withUpperCase().withPrefix("0x").withSuffix(", ").formatHex(bytes);
+    log.info("Hex value: {}", hex);
+  }
+}

backend/src/main/java/com/rdkr/tide_display/backend/images/services/MapService.java

@@ -0,0 +1,7 @@
+package com.rdkr.tide_display.backend.images.services;
+
+public interface MapService {
+
+    byte[] getStaticMap(double latitude, double longitude, int zoom);
+
+}

backend/src/main/java/com/rdkr/tide_display/backend/images/services/MapServiceImpl.java

@@ -0,0 +1,25 @@
+package com.rdkr.tide_display.backend.images.services;
+
+import lombok.val;
+import org.springframework.cache.annotation.Cacheable;
+import org.springframework.stereotype.Service;
+import org.springframework.web.client.RestClient;
+
+@Service
+public class MapServiceImpl implements MapService {
+
+  @Cacheable("map")
+  public byte[] getStaticMap(double latitude, double longitude, int zoom) {
+    val client = RestClient.create("https://maps.googleapis.com/maps/api/staticmap");
+    return client.get()
+        .uri(uriBuilder -> uriBuilder
+            .queryParam("center", latitude + "," + longitude)
+            .queryParam("zoom", "" + zoom)
+            .queryParam("size", "540x540")
+            .queryParam("map_id", "2f371c2346218fe8")
+            .queryParam("key", "AIzaSyARgP_FKFXsrcgVd_HVWoIfH5N8-a88wlQ")
+            .build())
+        .retrieve()
+        .body(byte[].class);
+  }
+}