Read JPEG File VI

Reads a JPEG file and creates the data necessary to display the file in a picture control.

Use the Draw Flattened Pixmap VI to display the bitmap you acquire with this VI. Use the Unflatten Pixmap VI to work with the data as a 2D array.

Note This VI automatically reads JPEG files as 24-bit images.


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Inputs/Outputs

  • cpath.png path to JPEG file —

    path to JPEG file specifies the path to and name of the JPEG file to read.

    If you do not specify a path, LabVIEW displays a file dialog box so the user can navigate to the file.

  • cerrcodeclst.png error in (no error) —

    error in describes error conditions that occur before this node runs. This input provides standard error in functionality.

  • cbool.png use 8 bit color table —

    use 8 bit color table reads the JPEG file at an 8 bit per pixel image depth instead of 24 bit per pixel image depth. The default value is FALSE.

  • ipath.png path —

    path specifies the path of the pixmap.

  • icclst.png image data —

    image data returns information about the image so you can use the Draw Flattened Pixmap VI to draw it as a picture.

  • ii32.png image type —

    image type is reserved for future use.

  • ii32.png image depth —

    image depth specifies the color depth of the image, which is the number of bits to use to describe the color of each pixel in the image. Valid values include 1, 4, 8, and 24 bits per pixel.

    image depth affects how LabVIEW interprets the values of image and colors.

  • i1du8.png image —

    image is an array of bytes that describes the color of each pixel in the image in raster order. The value of image depth determines how LabVIEW interprets the value of this output.

    If image depth is 24, each pixel has three bytes to describe its color. The first byte for each pixel describes the red value, the second byte describes the green value, and the third byte describes the blue value.

    If image depth is 8, each pixel has one byte to describe its color. The value of each bit corresponds to an element in colors, which stores 32-bit RGB values where the most significant byte is zero, followed in order by red, green, and blue values. Valid values include 0 through 255.

    The size of the array might be larger than expected due to padding.

  • i1du8.png mask —

    mask is an array of bytes in which each bit describes mask information for a pixel. The first byte describes the first eight pixels, the second byte describes the next eight pixels, and so on. In this VI, the mask array is always empty.

    Since the array is empty, LabVIEW draws all pixels without transparency.

  • i1du32.png colors —

    colors is an array of RGB color values that correspond to the values in image. The value of image depth determines how LabVIEW interprets the value of this output.

    If image depth is 24, LabVIEW ignores this output.

    If image depth is 8, the array can have 256 elements.

    If the array is empty for any depth other than 24 bits per pixel, the image is using the default LabVIEW color palette.

  • inclst.png Rectangle —

    Rectangle is a cluster that contains coordinates that describe the bounding rectangle of the image.

    Horizontal coordinates increase to the right, and vertical coordinates increase to the bottom.

  • ii16.png left —

    left is the horizontal coordinate of the left edge of the rectangle.

  • ii16.png top —

    top is the vertical coordinate of the top edge of the rectangle.

  • ii16.png right —

    right is the horizontal coordinate of the right edge of the rectangle.

  • ii16.png bottom —

    bottom is the vertical coordinate of the bottom edge of the rectangle.

  • ierrcodeclst.png error out —

    error out contains error information. This output provides standard error out functionality.