A raster graphic (or pixel graphic) is a data structure representing a generally rectangular grid of pixels or points of colo. It is viewable via a monitor, paper, or other display medium. Raster images are stored in image files with varying formats (like PNG (Portable Network Graphics), GIF (Graphics Interchange Format), and JPEG (Joint Photographic Experts Group), among others). A bitmap corresponds bit-by-bit with an image displayed on a screen. Generally the same format is used for storage in the display's video memory or, perhaps, as a device-independent bitmap. A bitmap graphic is technically characterized by the height and width of the image in pixels, by the number of bits per pixel and a color depth, which determines the number of colors it can represent. The word "raster" has its origins in the Latin word rastrum (a rake), which is derived from radere (to scrape). It recalls the systematic, horizontal sampling of a grid-pattern which is populated by individual pixel-spaces with a view to representing an overall image.

Raster Graphics in the LayoutEditor

Raster graphics can be used in two ways within the LayoutEditor. A raster graphic can be imported as a regular design or it can be used as an overlay background image. Such a background image can also be vectorized.

Raster Graphic as Design

Raster graphics that are loaded into a vector graphic program like LayoutEditor won't normally match. However, sometimes such an operation can be useful. For example, when adding a logo - only available as a bitmap file - to a given design. To do this, LayoutEditor converts each pixel into a box. There are two ways of importing an image (see list below). Most of the common raster graphic formats are supported by LayoutEditor however specific formats may only be available on certain platforms. Resolution (size per pixel) is assignable. By default, the user units are used to define resolution. Exported files with more than 530MPixel are split into multiple files. Exports to raster graphics will save visible layers of the current cell. To export part of a cell, please use the screenshot or print function.

Import Method: Map Colors to Layers

The LayoutEditor converts every pixel to a box on the layer whose color is the closest to the original pixel color. This may lead to unsatisfactory results because of limits on available colors. The SetupDialog allows users to activate an option to optimize existing layer colors which can produce a better color import.

Import Method: Grey Scale with Dithering

This method is used to import images in grey scale. A box is added for each pixel and the edge-size is adjusted to the grey value of the image pixel. The Floyd-Steinberg method is used for dithering. The minimal allowed box-size for a pixel can be set up, along with the number of allowed sizes for pixel shapes. A positive/negative context can be set up. Users can choose whether a full-size pixel box represents a white or black image pixel.

Raster Graphic as Background

Use the SetBackgroundImagefeature to add a raster graphic image as a background. The loaded graphic can be aligned and scaled afterwards. It is possible to load multiple graphics into one design. The image will be used as a background for any displayed cell. Merge a loaded background image into the design using the VectorizeImages feature.