Talk:Raster graphics

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"A bitmap corresponds bit-for-bit with an image displayed on a screen, generally in the same format used for storage in the display's video memory, or maybe as a device-independent bitmap." Should the word "maybe" be used here? It doesn't sound right.

—Preceding unsigned comment added by The MP (talkcontribs) 00:56, 9 December 2008 (UTC)

Cant be rescaled without significant loss of quality? I dont really understand this. scaling DOWN loses NO quality if you ask me. scaling up, though it loses no absolute quality, it lowers the relative quality.

Scaling down clearly loses quality. What if I scale down to a single pixel? If by quality you mean information per pixel then you may be right, but that's not what most people mean. --drj

The terms "Vector" vs. "Raster" graphics originally derived from display technology. Vector dislays moved the CRT beam from point to point to draw straight line segments, whereas the CRT beam in a raster display scanned a fixed pattern like a TV. Displaying a circle on a raster display required scan-conversion (determining the points where the scan line intersected the circle), whereas displaying a circle on a vector display required vectorization (fitting many short vectors to approximate the circle). Scaling a vectorized circle meant scaling the vectors, which did not preserve the accuracy of the approximation. To maintain fidelity it was necessary to scale the circle geometrically and then re-vectorize. A circle can similarly be scaled geometrically and then re-scan-converted for a raster display. The approach is perhaps more accurately termed "geometric graphics".

That's true, and perhaps something of this origin of the terms should be included in that artice. But regardless of the origin of the terms, their most common present use is merely to distinguish "scanned" graphics from "object-based" graphics. This is even how the terms are used in modern graphics file format specs, and what they are likely to mean when encountered by our audience. I haven't seen an actual vector CRT since the old Atari coin-op video game "Tempest", but people do talk about things like PDF and SVG as "vector" graphics, and in that context, scalability (i.e., the fact that the image is defined in terms of an ideal that can be rendered to the limits of whatever device is available) is a primary feature (that's even what the "S" in SVG stands for). --LDC

Here's what the Microsoft Press Computer Dictionary (3rd ed. 1997) has to say...

vector graphics images generated from mathematical descriptions that determine the position, length, and direction in which lines are drawn. Objects are created as collections of lines rather than as patterns of individual dots or pixels.
object-oriented graphics computer graphics that are based on the use of graphics primitives, such as lines, curves, circles, and squares...

The IBM Dictionary of Computing (10th ed. 1994) has:

vector graphics - see coordinate graphics
coordinate graphics - Computer graphics in which display images are generated from display commands and coordinate data. Contrast with raster graphics. Synonymous with line graphics.

On the other hand, Robin Williams in Jargon: An Informal Dictionary of Computer Terms (1993) says:

The term vector graphics means exactly the same thing as object-oriented (or just object) graphics.

I suspect the confusion in terminology is due to people (perhaps unfamiliar with the word "vector") incorrectly using "vector graphics" as an antonym for "raster graphics".

If you think it's worthwhile to retain the older meaning of "vector" (perhaps to ease confusion with math articles about vectors), then perhaps we could have a "vector graphics" page with something like "The term vector graphics is commonly used today as a synonym for object graphics, though originally it referred to...", and the establish a Wikipedia style guideline to use "object graphics" exclusively. My hesitation to do this is that the misuse of the term really is well-entrenched, and it might be more confusing to use to "correct" term. --LDC

I definitely think the original meaning and context should be included, if only for historical reference. Whether we should attempt to discourage the use of the term in its new sense in favor of "object graphics", I don't know.

Is "raster graphics" the proper name for this page?

The expression "raster graphics" came into use many years ago (70's or earlier) to distinguish computer graphics algorithms appropriate for the "new" bitmap-based displays, from the older ones oriented twoards direct-drawing displays ("vector graphics"). Since "vector graphics" are dead, the name is no longer meaninful.

Also, the term "bitmap" was coined (in the early 80's) to refer specifically to *binary* images stored in memory. ("Advanced" workstations then had only 64K bytes of memory for everything!) Even today "bitmap" is used in non-graphics contexts to stand for "compact *boolean* array". When color raster graphics became popular some people may have continued using "bitmap" out of habit, but others used more appropriate names like "bytemap", "pixmap", "pelmap".

Nowadays "raster graphics" is supported by a "frame buffer" in the video card, rather than a "bitmap" in memory. If/when a programmer needs to describe the data structure used to represent a digital image in main memory, I think he would rather use "image object", "pixel array", "image in memory", etc. -- rather than "bitmap".

Finally, this page mixes the system programming concept of "bitmap" (a data structure in computer memory) with the signal processing concept of "digital image" (an abstract array of samples). Issues like resolution, scaling etc. belong to the latter, not the former.

So here is my proposal:

  1. Create a new page for "digital image" [done!] and move to it those parts of the present "raster graphics" page that apply to digital images independently of memory layout.
  2. Create a new page called "raster map" aka "pixel array" that describes the data structure in question (a packed 2D array of bits or small integers) and its main uses -- namely, storing a digital image in memory, and as a frame buffer. This page should include "bitmap"as a special case. (Or perhaps "bitmap" should have a separate page due to its use for non-image applications?)
  3. Reduce the "raster graphics" page to a single paragraph, "A term coined in the 70's to distinguish computer graphics techniques bla bla...from "vector raphics" bla bla...
  4. Create links between the "raster map" and "frame buffer" pages.

What do you think? -- 08:52, 4 Mar 2004 (UTC)Jorge Stolfi

  • Vector graphics does not just refer to a type of display, but also to storing coordinates of vertices, etc. rather than pixel data, that is not dead. --Patrick 00:49, 5 Mar 2004 (UTC)

Ok, I should have said "vector graphics *displays* are dead".

Storing vertices etc. is certainly more alive than ever --- that is what goes into the typical graphics card, or what you put in a Postscript file; but I think that the proper name for that is (2D) *geometric modeling*.

That nomenclature would be consistent with common usage in 3D graphics: The representation of the scene with vertices, edges, faces etc. is called the *geometric model*. By rendering this model (at a chosen scale and resolution) one obtains produces a (raster) digital image, which goes to the display device.

Note that your 2D "vector graphics" similarly must be converted to a digital image before it can be displayed. That is the job of the graphics card, Postscript interpreter, etc. At that moment one must choose a rendering window and resolution (and lose information), just as in 3D graphics.

In other words, the concepts of "vector graphics" and "raster graphics" are no longer two mutually exclusive alternative ways of doing computer graphics, but rather two succesive *stages* of it. Thus those names (which embodied the either/or view) are no longer adequate.

Analog raster graphics[edit]

Should the article link to halftone printing as a halftone print is essentially composed of dots, an analog raster image. Scoo 09:43, 20 July 2006 (UTC)

The article is not too detailed....................... Thumbs down

Better explanation of value of raster graphics, contrasted with vector graphics[edit]

Note the following passage in the raster graphics article:

Raster graphics deal more practically than vector graphics with photographs and photo-realistic images . . . . [Italics added]

The article does not explain this greater practicality. Reading the voctor graphics article, one is impressed with the use of vector graphics in producing sharper images. So, one wonders why bother with raster graphics. Furthermore, one notices that Paint Shop Pro handles raster graphics, while Photoshop does not. What does Corel know that Adobe does not, or vice versa? Dogru144 16:27, 8 August 2007 (UTC)

Speaking of analog photos, which type of graphic editing (raster or vector) is better? Cheers, Dogru144 16:27, 8 August 2007 (UTC)

Mention of Some Formats?[edit]

It'd be great if mention or links could be made to some formats e.g. GIF, JPEG, & BMP.

Any others?


JohnI 22:54, 29 August 2007 (UTC)

Done. I just added visible links to two other pages that cover that. We definately don't want this article to turn into a looooong list of graphics file formats. --Kubanczyk 07:50, 19 September 2007 (UTC)


I have reverted wholesale spelling changes on this article enough, so someone else feel free to do it instead. From now on I'm just going to keep it consistent one spelling or the other. VMS Mosaic 17:51, 19 September 2007 (UTC)

this is comfusing. —Preceding unsigned comment added by (talk) 19:41, 3 November 2007 (UTC)

Merging “bitmap”?[edit]

Is there notable examples of raster graphics, which are not bitmap in the sense of that article? (Do not confuse it with binary image which is a separate article.) May be, so named analog raster graphics? But such unquantized things as analog video are not commonly referred as raster graphics, and may be noted as See also.

I propose to merge the article “bitmap” here, and move bitmap (disambiguation) to bitmap, see Talk:Bitmap#What concept is the article about?. Incnis Mrsi (talk) 12:50, 20 January 2009 (UTC)

I have to agree. Besides, they are in a sense one and the same. Adam Hillman (talk) 12:12, 5 March 2009 (UTC)
  • Oppose – In general, I'm not in favor of merging a decent sourced article into a messed up unsourced article. If we're going to do a merge, I'd look for what in raster graphics can be sourced, and then decide whether it overlaps the content of bitmap enough to support a merge, and then decide which direction to go. At present, I'd say merge the meager content of raster graphics into bitmap, though they could also be kept distinct; their present contents do not actually overlap much. Dicklyon (talk) 18:18, 5 March 2009 (UTC)
  • Oppose while a bitmap does fall under raster graphics so do more complex formats such as OpenRaster and PSD. I suggest we put a sub section in marked {{main | Bitmap}}, Bitmap is a descent sized and sourced somewhat article now and I believe it will be pushed into its own article in the future if merged anyhow. --Gnepets (talk) 01:41, 18 June 2009 (UTC)

Merge bitmap into here?[edit]

I have no dog in this fight, but I’m curious why JohnnyMrNinja merged the "Bitmap" article into here even though there seems to be more opposition than support for such a merger. [edit: in the previous section] –jacobolus (t) 10:14, 12 February 2011 (UTC)

I'd have participated in the "fight" myself, but I lost the keys to my time machine. The debate is about the article in June 2009, which was about both bitmap file formats in general (i.e. raster graphics) and the Bitmap file format. The latter was later split off into its own article, leaving the two pages completely redundant. Thanks for the vote of confidence. ▫ JohnnyMrNinja 10:29, 12 February 2011 (UTC)
Ah, fair point. I didn’t look as closely as I should have. Well, it should probably be put to another discussion then. I moved this to a new section. Does anyone have a high-level vision for how these pages should ideally be organized? Does a merger, now in 2011, seem like a good idea to people? –jacobolus (t) 11:50, 12 February 2011 (UTC)
I'm still going for yes on this one, the current version is a complete overlap. ▫ JohnnyMrNinja 06:52, 14 February 2011 (UTC)
Agreed! Should be one. -rjdthegreat — Preceding undated comment added 21:01, 23 June 2015 (UTC)

As I said before, "I'm not in favor of merging a decent sourced article into a messed up unsourced article." Merge the other direction, and lose the ugly smiley face if you want to improve matters. Dicklyon (talk) 16:06, 14 February 2011 (UTC)


I doubt that the rastrum theory is correct. I would like to see a source for it. In Dutch, "rooster" means grid, and this word sounds similar to raster.


It would be easier for users to find the articles if they were merged, but I notice they both talk abount different things at some points. If the Raster Image article were to be cleaned up a bit, then merging could definitely be a possibility. talk 18:18, 25 October 2012 (UTC)