Module com.github.librepdf.openpdf.parent
Package org.openpdf.util

Class ImageUtil

java.lang.Object
org.openpdf.util.ImageUtil
public class ImageUtil extends Object
Static utility methods for working with images. Meant to suggest "best practices" for the most straightforward cases of working with images.
Author:
pwright

  • Constructor Details

    • ImageUtil

      public ImageUtil()

  • Method Details

    • clearImage

      public static void clearImage(BufferedImage image)
      Sets the background of the image to white

    • withGraphics

      public static void withGraphics(BufferedImage image, Consumer<Graphics2D> block)

    • withGraphics

      public static void withGraphics(Graphics graphics, Consumer<Graphics> block)

    • makeCompatible

      @CheckReturnValue public static BufferedImage makeCompatible(BufferedImage image)

    • createCompatibleBufferedImage

      @CheckReturnValue public static BufferedImage createCompatibleBufferedImage(int width, int height, int biType)
      Helper method to instantiate new BufferedImages; if the graphics environment is actually connected to real screen devices (e.g. not in headless mode), the image will be compatible with the screen device allowing for best performance. In a headless environment, simply creates a new BufferedImage. For non-headless environments, this just sets up and calls GraphicsConfiguration.createCompatibleImage(int,int,int). The image will not have anything drawn to it, not even a white background; you must do this yourself. The clearImage(BufferedImage) method will do this for you if you like.
      Parameters:
      width - Target width for the image
      height - Target height for the image
      biType - Value from the BufferedImage class; see docs for BufferedImage(int,int,int). The actual type used will be the type specified in this parameter, if in headless mode, or the type most compatible with the screen, if in non-headless more.
      Returns:
      A BufferedImage compatible with the screen (best fit).

    • createCompatibleBufferedImage

      @CheckReturnValue public static BufferedImage createCompatibleBufferedImage(int width, int height)
      Creates a BufferedImage compatible with the local graphics environment; this is a helper method for a common process and just sets up and calls GraphicsConfiguration.createCompatibleImage(int,int,int). The image will support transparent pixels.
      Parameters:
      width - Target width for the image
      height - Target height for the image
      Returns:
      A BufferedImage compatible with the screen (best fit) supporting transparent pixels.

    • getScaledInstance

      @CheckReturnValue public static BufferedImage getScaledInstance(ScalingOptions opt, BufferedImage orgImage)
      Scales an image to the requested width and height, assuming these are both >= 1; size given in pixels. If either width or height is invalid input: '<'=0, the current image width or height will be used. This method assumes that, at the moment the method is called, the width and height of the image are available; it won't wait for them. Therefore, the method should be called once the image has completely loaded and not before.

      Override this method in a subclass to optimize image scaling operations; note that the legacy Image.getScaledInstance(int, int, int) is considered to perform poorly compared to more recent developed techniques.

      For a discussion of the options from a member of the Java2D team, see ...

      Parameters:
      orgImage - The image to scale
      Returns:
      The scaled image instance.

    • getScaledInstance

      @CheckReturnValue public static BufferedImage getScaledInstance(BufferedImage orgImage, int targetWidth, int targetHeight)
      Scales an image to the requested width and height, assuming these are both >= 1; size given in pixels. If either width or height is invalid input: '<'=0, the current image width or height will be used. This method assumes y that, at the moment the method is called, the width and height of the image are available; it won't wait for them. Therefore, the method should be called once the image has completely loaded and not before.

      Override this method in a subclass to optimize image scaling operations; note that the legacy Image.getScaledInstance(int, int, int) is considered to perform poorly compared to more recent developed techniques.

      For a discussion of the options from a member of the Java2D team, see ...

      Parameters:
      orgImage - The image to scale
      targetWidth - The target width in pixels
      targetHeight - The target height in pixels
      Returns:
      The scaled image instance.

    • convertToBufferedImage

      @CheckReturnValue public static BufferedImage convertToBufferedImage(Image awtImg, int type)
      Utility method to convert an AWT Image to a BufferedImage. Size is preserved, BufferedImage is compatible with current display device.
      Parameters:
      awtImg - image to convert; if already a BufferedImage, returned unmodified
      type - the type of BufferedImage to create; see BufferedImage(int,int,int)
      Returns:
      BufferedImage with same content.

    • createTransparentImage

      @CheckReturnValue public static BufferedImage createTransparentImage(int width, int height)

    • isEmbeddedBase64Image

      @CheckReturnValue public static boolean isEmbeddedBase64Image(@Nullable String uri)
      Detect if given URI represents an embedded base 64 image.
      Parameters:
      uri - URI of the image
      Returns:
      A boolean

    • getEmbeddedBase64Image

      @CheckReturnValue public static byte @Nullable [] getEmbeddedBase64Image(String imageDataUri)
      Get the binary content of an embedded base 64 image.
      Parameters:
      imageDataUri - URI of the embedded image
      Returns:
      The binary content

    • loadEmbeddedBase64Image

      @CheckReturnValue public static @Nullable BufferedImage loadEmbeddedBase64Image(String imageDataUri)
      Get the BufferedImage of an embedded base 64 image.
      Parameters:
      imageDataUri - URI of the embedded image
      Returns:
      The BufferedImage