Generating, storing, and displaying graphics using sub-pixel bitmaps

• US 7,570,828 B2
• Filed: 03/16/2007
• Issued: 08/04/2009
• Est. Priority Date: 03/23/2004
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Rasmussen, Lars Eilstrup, Rasmussen, Jens Eilstrup
• Primary Examiner(s): Tung; Kee M
• Assistant Examiner(s): Chu; David H
• Application Number:
  US11/687,168
• Publication Number:
  US 20070182751A1
• Time in Patent Office: 872 Days
• Field of Search: 345/613, 382/245
• US Class Current: 382/245
• CPC Class Codes: G01C 21/367 Details, e.g. road map scale, orientation, zooming, illumination, level of detail, scrolling of road map or positioning of current position marker
• CPC Class Codes: G01C 21/3881 Tile-based structures
• CPC Class Codes: G06F 16/9537 Spatial or temporal dependent retrieval, e.g. spatiotemporal queries
• CPC Class Codes: G06Q 40/12 Accounting
• CPC Class Codes: G06T 11/40 Filling a planar surface by adding surface attributes, e.g. colour or texture
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G06T 3/40 Scaling of whole images or parts thereof, e.g. expanding or contracting
• CPC Class Codes: G09B 29/003 Maps
• CPC Class Codes: G09B 29/004 Map manufacture or repair; Tear or ink or water resistant maps; Long-life maps printing processes for maps B41M3/02; by permanently attaching map sections to sheets B42B7/00
• CPC Class Codes: G09B 29/10 Map spot or coordinate position indicators; Map reading aids optical projection apparatus per se G03B
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

Techniques for generating, storing and displaying graphics on computer systems are disclosed. The type of graphics in particular are images, where the image can be defined as a set of areas, whether these areas are lines, geometric shapes, letters or other types of areas. The effect of using these methods is that graphics, such as digital maps, can be handled faster, with more flexibility and with higher display quality, both for screen use and for printing.

Claims

1. A method for generating sub-pixel bitmaps of images comprising pixels, the method comprising:

for each pixel in an image identifying color information by;

responsive to the pixel comprising multiple colors;

for each color, assigning a weight to the color based on a proportion of area of the pixel that is covered by the color; and

storing the identified color information for each pixel of the image as a sub-pixel bitmap using run-length encoding to store the identified color information as alternating sequences of single color pixels and multi-color pixels.

2. The method of claim 1, further comprising:

reducing the number of colors per pixel.

3. The method of claim 1, further comprising:

using a supplemental printing tile to provide a higher resolution bitmap without anti-aliasing, as compared to the sub-pixel bitmap, to enable high resolution printing.

4. The method of claim 1, wherein color for a pixel with more than one source is calculated based on the colors that cover parts of the pixel, weights assigned to those colors to indicate by how much the color covers the pixel, and a display gamma value.

5. The method of claim 1 further comprising reducing a maximum number of colors per pixel in the image to two colors.

6. A method of generating a sub-pixel bitmap of an image, the image comprising pixels each having one or more sources that define the color of the respective pixel when displayed, the method comprising:

for each pixel in the image, identifying source information by;

responsive to the pixel having more than one source;

for each source, assigning a weight to the source based on a proportion of area of the pixel that is covered by the source; and

storing the identified source information for each pixel of the image as a sub-pixel bitmap using run-length encoding to store the identified source information as alternating sequences of single source pixels and multi-source pixels.

7. The method of claim 6, further comprising reducing the number of sources per pixel to a maximum of two.

8. The method of claim 6, further comprising:

using a supplemental printing tile to provide a higher resolution bitmap without anti-aliasing, as compared to the sub-pixel bitmap, to enable high resolution printing.

9. The method of claim 6, wherein color for a pixel with more than one source is calculated based on the colors that cover parts of the pixel, weights assigned to those colors to indicate by how much the color covers the pixel, and a display gamma value.