Rastergrafikas

Rastergrafikas, or raster graphics, are digital images defined by a grid of individual picture elements called pixels. Each pixel stores color information, and the image emerges from the collective values. Raster images are pixel-based and are commonly used for photographs and complex color imagery. They differ from vector graphics, which describe shapes mathematically and can be scaled without quality loss.

Key characteristics include resolution dependence and color depth. Enlarging a raster image increases visible pixelation and may degrade quality. Typical color depth is 8 bits per channel (24 bits per pixel in standard true color), though higher depths exist. Common file formats are JPEG (lossy), PNG (lossless), GIF (indexed color with a limited palette), BMP, TIFF, and WebP; some formats support alpha transparency. The resulting file size depends on resolution, color depth, and compression.

Raster images are produced by cameras, scanners, or rendering processes and are displayed by rasterizing vectors when needed. Editing operations such as scaling, rotating, filtering, and color adjustments modify pixel values. Techniques like anti-aliasing help smooth edges, while dithering can approximate colors in limited palettes.

Color management and metadata are important in raster graphics. Color spaces such as sRGB are standard for web, with gamma correction influencing brightness perception. Metadata, including EXIF in photography, records information about capture settings and processing. Compression can introduce artifacts, especially in lossy formats.

Applications span digital photography, web graphics, textures in 3D rendering, video frames, and user interface imagery. Raster graphics are edited in software such as Photoshop, GIMP, Affinity Photo, and Paint.NET, where balance between fidelity and file size is a common consideration.