Topic: raster graphics

topics > computer science > user interface > Group: graphical user interface

icons for a user interface
implementation of user interfaces
page formatting


Raster graphics uses a bitmap to control pixels on a display. It has largely replaced vector graphics where a terminal draws lines and other shapes directly. Raster graphics and the corresponding BitBlt operator is a key component of the graphical user interface. The BitBlt operator may be used for placing images, scaling, and other operations. Color is widely used now.

At the user-level, objects typically represent a portion of a graphics display. The objects may overlap and move independently. Floating-point properties provide greater flexibility than pixel measurements.

Raster graphics have been used for audience interaction, and to represent large data sets directly. (cbb 4/98)

Subtopic: bitmap display up

Quote: Sketchpad uses a Tx-2 scope that displays upto 100,000 spots/second on a 1024x1024 grid [»suthIE5_1963]
Quote: 36-bits per spot for display location and an n-component element; e.g., the spots for a subpicture point to that subpicture's ring [»suthIE5_1963]
Quote: a bitmap display uses a block of bits to turn on and off pixels on the screen [»ingaDH8_1981]
Quote: Smalltalk is based on object-oriented processing and a bitmap for visual display [»ingaDH8_1981a]
Quote: Star and Alto use a bit-mapped display [»smitDC4_1982]
Quote: Oberon display is organized into frames (a rectangular bit map with subframes)
Quote: a Smalltalk 'Form' has height, width, and a bitmap of some image [»ingaDH8_1981]

Subtopic: BitBlt up

Quote: BitBlt is crucial to Smalltalk's user interface; need to optimize its performance [»ingaDH8_1981]
Quote: the BitBlt copy operation transfers a bits in a source form to a destination [»ingaDH8_1981]
Quote: BitBlt includes a clipping rectangle to restrict the display to a rectangle [»ingaDH8_1981]
Quote: BitBlt has a halftoneForm to fill an area with a regular pattern [»ingaDH8_1981]
Quote: BitBlt allows pixels from the source and destination to be combined in any way, e.g., paint under with an 'or' [»ingaDH8_1981]
Quote: Smalltalk displays text by BitBlt from a font form containing the character glyphs [»ingaDH8_1981]
Quote: Squeak usually uses one word of overhead per object, incremental garbage collection, bulk-mutation, extended BitBlt, multi-media

Subtopic: line drawing up

Quote: leap year calculations are a generalization of Bresenham's algorithm for drawing lines [»harrMA3_2004]

Subtopic: raster operations up

Quote: can use BitBlt to rotate an image [»ingaDH8_1981]
Quote: XOR for moving graphics is not very portable; e.g., fails for color displays [»pausR10_1992]
Quote: magnify a bit image by slicing into vertical strings, smearing the bits by ORing, and doing the same for horizontal strings [»ingaDH8_1981]
Quote: display data in miniature if not enough room; zooming displays more information [»browMH5_1988]
Quote: selected objects in SUIT display black handles with a 1-pixel wide white border; always visible [»pausR10_1992]
Quote: in Smalltalk, measure a line for cursor tracking by printing it with the 'printing' flag false; easier to maintain and optimize [»ingaDH8_1981]

Subtopic: shared background up

Quote: HyperCard pictures, buttons, and fields either on shared background or individual cards [»willG12_1987]

Subtopic: color bitmaps up

Quote: color requires fewer pixels than shape; also better for global patterns in an animation [»browMH12_1992]

Subtopic: structured bitmaps up

Quote: tree maps show 2-3 thousand hierarchical nodes by encoding information as a rectangle, with a color and sound; e.g., TreeViz for directories [»shneB1_1993]

Subtopic: large-scale bitmaps up

Quote: in Audience Participation, each wand controlled one pixel; the group quickly learned to control information; focused interest [»giloCF10_1991]

Subtopic: object-oriented vs. bitmap up

Quote: the object-oriented graphics interface (as in MacDraw) is better than bit-mapped graphics for most direct manipulation applications [»mohaMF3_1991]
Quote: students preferred drawing in screen pixels until they had written several custom widgets; floating point easier and more abstract [»pausR10_1992]

Related Topics up

Topic: animation (20 items)
Topic: graphics (16 items)
Topic: icons for a user interface (23 items)
Topic: implementation of user interfaces (18 items)
Topic: page formatting
(16 items)

Updated barberCB 12/04
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