Documentation/AOO4 User Guides/Draw Guide/Editing Pictures Raster Graphics/The Graphic Filter Toolbar

Apache OpenOffice 4.1 Draw Guide

Editing Pictures (Raster Graphics)

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• Introduction
• Importing Raster and Vector Graphics
  • Link or Embed?
  • Scanning
  • Pasting from the Clipboard
  • Dragging and Dropping
  • Inserting from a File
• Exporting Graphics
  • Exporting the Entire File
  • Exporting Single Objects
  • Exporting as a Vector Graphic
  • Exporting as a Raster Graphic
• Modifying Raster Object Properties
• The Picture (Editing) Toolbar and Graphic Pane
• Cropping
• The Graphic Filter Toolbar
• Changing Colors Using the Color Replacer
  • Practical Example: Changing Wrong Colors to Transparency
  • Effect of the Tolerance Parameter
  • Color Depth
    • Reducing color depth
• Conversion
  • Convert to a Contoured Image
  • Convert to a Polygon
    • Number of Colors
    • Point Reduction
    • Fill Holes
  • Convert to Bitmap
• Print Options with Raster Graphics

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The Graphic Filter Toolbar

Click the Filter icon to open the Filter toolbar. Draw offers eleven filter effects. Filters work on the current view of an object, and can be combined. Filters always apply to the entire graphic; it is not possible to use filters to edit only a part of the object.

	Invert reverses (inverts) the colors of an image so that it appears as a color negative of the image.
	Smooth reduces the contrast between neighboring pixels, resulting in a slight loss of sharpness. If you use the filter several times in a row, the effect will be strengthened.
	Sharpen increases the contrast between neighboring pixels, emphasizing the brightness difference. This will accentuate the outlines. The effect will be strengthened if you apply the filter several times in a row.
	Remove noise compares every pixel with its neighbors and replaces the extreme values (those that deviate in color by a large amount from a mean value) by a pixel with a mean color value. The amount of picture information does not increase, but because there are fewer contrast changes, our brains can better recognize the resulting graphic. This filter tends to make the picture a little smoother.
	Solarization was originally a photochemical effect. If the location of a photograph is extremely highly lit, you can experience a reversal of color and brightness. Similarly, entry of light during the developing process reverses the brightness values. These phenomena were used for artistic production of pictures. With this filter, you input a threshold brightness value, above which the color values are reversed (middle picture, threshold value 70%). With the Invert option, the whole of the resulting picture is inverted in color (right picture).
	Aging lends pictures a certain “look” resembling that of old photos. The process first produces a grayscale picture from the original and then reduces the intensity of the blue and green color values, so that the final picture appears darker and redder. In the middle example, the aging degree was set to 0%, on the right it was 15%.

	Posterize reduces the number of colors in the picture. The fewer colors, the flatter the picture appears. In the picture below on the right, the number of colors was reduced to 8. The results of this filter are not always good.
	The Pop-Art filter is supposed to change the colors of the picture to a pop-art format, but unfortunately, it does not seem to function correctly at present.
	Charcoal sketch makes the picture appear as if it had been drawn with charcoal. The outlines are in black, and the original colors are suppressed.
	The Relief filter calculates the edges in relief of the picture and produces a picture as if illuminated by a light source, the position of the illuminating light being variable and producing shadows that differ in direction and magnitude.
	Mosaic takes groups of pixels and converts them into a single color rectangular tile. The whole picture appears to be a mosaic. The center and right pictures below had an element resolution of 5 pixels. The picture on the right also had the Enhance edges option selected; with the greater contrast at the edges, it appears to be a little sharper.

If your picture is linked, filters are applied only to the current view. The stored picture is not changed. When you close the document, all filtering is lost. You should ensure that you export the picture to create a copy with all the filters applied (File