BackgroundImageSave.java

package net.hearthstats.game.ocr;

import java.awt.image.BufferedImage;
import java.io.File;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import javax.imageio.ImageIO;

import net.hearthstats.game.ScreenConfig;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Saves images on a background thread so that detection isn't held up by a slow filesystem.
 *
 * @author gtch
 */
public class BackgroundImageSave {

  private static final Logger debugLog = LoggerFactory.getLogger(BackgroundImageSave.class);

  private static final ExecutorService backgroundThreadExecutor = Executors.newSingleThreadExecutor();

  private static String saveFolder;


  /**
   * Saves a PNG image in the temp/extraction folder, doing so on a background thread so that detection isn't held up.
   *
   * @param image    The image to save. You should not make any further changes to this image on the main thread after
   *                 submitting it to this method, otherwise the save file will have unpredictable contents.
   * @param filename The name of the file to save. Do not include the extension (.png is added automatically)
   */
  public static void savePngImage(final BufferedImage image, final String filename) {
    debugLog.debug("savePngImage({}, {})", image == null ? null : image.getWidth(), filename);
    if (image == null) {
      debugLog.warn("Could not save image {} because image is null", filename);
      return;
    } else if (StringUtils.isBlank(filename)) {
      debugLog.warn("Could not save image because filename is blank");
      return;
    }

    backgroundThreadExecutor.submit(new Runnable() {
      @Override
      public void run() {
        try {
          File outputfile = new File((saveFolder == null ? filename : saveFolder + "/" + filename) + ".png");
          ImageIO.write(image, "png", outputfile);
          debugLog.debug("Successfully saved image " + outputfile.getAbsolutePath());
        } catch (Exception e) {
          debugLog.warn("Error saving image " + filename, e);
        }

        if (image != null) {
          image.flush();
        }
      }
    });

  }


  /**
   * <p>Saves a PNG image in the temp/extraction folder, cropped as specified. Ths image is saved on a background thread
   * so that detection isn't held up.</p>
   * <p>The code assumes that it has been given a full-size Hearthstone screenshot, and so the position of the crop
   * is adjusted to the relative position for the actual screen in the image. In other words, if the screenshot is
   * higher resolution or lower resolution than the reference 1600x1200 size then the crop is moved accordingly.</p>
   *
   * @param image    The image to save. You should not make any further changes to this image on the main thread after
   *                 submitting it to this method, otherwise the save file will have unpredictable contents.
   * @param filename The name of the file to save. Do not include the extension (.png is added automatically)
   * @param x        the X coordinate of the upper-left corner of the crop, relative to a 1600-pixel wide screen
   * @param y        the Y coordinate of the upper-left corner of the crop, relative to a 1200-pixel high screen
   * @param w        the width of the specified rectangular region, relative to a 1600-pixel wide screen
   * @param h        the height of the specified rectangular region, relative to a 1200-pixel high screen
   */
  public static void saveCroppedPngImage(final BufferedImage image, final String filename, int x, int y, int w, int h) {
    float ratio = ScreenConfig.getRatio(image);
    int xOffset = ScreenConfig.getXOffset(image, ratio);

    int relativeX = (int) (x * ratio + xOffset);
    int relativeY = (int) (y * ratio);
    int relativeWidth = (int) (w * ratio);
    int relativeHeight = (int) (h * ratio);

    debugLog.debug("Cropping image to x={} y={} width={} height={}", relativeX, relativeY, relativeWidth, relativeHeight);

    BufferedImage croppedImage = image.getSubimage(relativeX, relativeY, relativeWidth, relativeHeight);
    savePngImage(croppedImage, filename);
  }


  /**
   * Sets the location where images will be saved.
   * @param saveFolder A folder/directory path.
   */
  public static void setSaveFolder(String saveFolder) {
    BackgroundImageSave.saveFolder = saveFolder;
  }


}