Raster graphics editor
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A raster graphics editor is a computer program that allows users to paint and edit pictures interactively on the computer screen and save them in one of many popular "bitmap" or "raster" formats such as JPEG, PNG, GIF and TIFF.
A raster graphics editor supports a certain repertoire of image editing operations.
Some editors specialize in the editing of (digital) photographs such as the popular Adobe Photoshop or RawTherapee, while others are more geared to artist-created illustrations, like the Adobe Fireworks.
Usually an image viewer is preferred over a raster graphics editor for viewing images.
Vector editors vs raster graphics editors
Vector graphics editors are often contrasted with raster graphics editors, yet their capabilities complement each other. The technical difference between Vector and Raster editors stem from the difference between vector and raster images. Vector images are created mathematically (using formulas, as in geometry). Each element is created and manipulated numerically; essentially using Cartesian coordinates for the placement of key points, and then a mathematical algorithm to connect the dots and define the colors.
Raster images include digital photos. A raster image is made up of pixels, and is generally more photo-realistic. This is the standard form for digital cameras; whether it be .raw format or .jpg, the concept is the same. The image is represented pixel by pixel, dot by dot, almost like a micro jigsaw puzzle where each pixel is a puzzle piece.
Vector editors tend to be better suited for graphic design, page layout, typography, logos, sharp-edged artistic illustrations (e.g. cartoons, clip art, complex geometric patterns), technical illustrations, diagramming and flowcharting.
Advanced raster editors (like Photoshop) use vector methods (mathematics) for general layout and elements such as text, but are equipped to deal with raster images down to the pixel and often have special capabilities in doing so, such as brightness/contrast, and even adding "lighting" to a raster image or photograph.
Raster editors are more suitable for retouching, photo processing, photo-realistic illustrations, collage, and hand drawn illustrations using a graphics tablet. Many contemporary illustrators use Corel Photo-Paint, Photoshop, GIMP, and other raster editors to make all kinds of illustrations. 21st century versions of such editors support vector-like tools (e.g. editable paths),
- Select a region for editing.
- Draw lines with brushes of different color, size, shape and pressure
- Fill in a region with a single color, gradient of colors, or a texture.
- Select a color using different color models (e.g. RGB, HSV), or by using a color dropper.
- Edit and convert between various color models.
- Add typed letters in different font styles.
- Remove scratches, dirt, wrinkles, and imperfections from photo images.
- Composite editing using layers.
- Apply filters for effects including sharpening and blurring.
- Convert between various image file formats.