Microsoft Technology Licensing, LLC

Microsoft Corporation

Claude Betrisey

Bodin Dresevic

Gregory Carl Hitchcock

Beat Stamm

John Carlton Platt

Matt Conway

Mohammed El-Gammal

Mikhail Lyapunov

Mikhail V Leonov

Donald P Mitchell

David Colin Wilson Brown

Mikhail M Lyapunov

David Colin Brown

Mohammed Gaber El-Gammal

Gregory C Hitchcock

Automatically positioning of typographical features, such as vertical stems or horizontal segments of a character, on high contrast pixel sub-component boundaries as part of a rendering process that uses separately controllable pixel sub-components of pixels to represent different portions of the character. In order to identify the typographical features of the character that are to be aligned with high contrast pixel sub-component boundaries, topology of the character is analyzed at runtime. In display devices having vertical stripes of same-colored pixel sub-components, character legibility is increased when the left edges of stems are aligned with high contrast boundaries between pixel sub-components. Processing time and resources are conserved by performing a partial, rather than a full, topological analysis of the character. For example, some font files include data structures that define the position of key control points associated with the character, thereby indicating where the stems or other typographical features are located, and the relationship between different typographical features.

Automatic optimization of the position of stems of text characters

Methods and apparatus for displaying images, e.g., text characters, on display devices which have multiple separately controllable luminance elements per pixel. Multiple alpha values are generated per pixel, e.g., one per pixel sub-component. Filtering is then performed to generate a filtered alpha value for each pixel sub-component. The filtering operation uses as its input multiple alpha values. The alpha values used for the filtering operation may come from neighboring pixels. Accordingly, in the case where character glyphs are combined to form larger images, e.g., text strings, the filtering operation performed on glyph edge pixels depends on the content of a neighboring character glyph. In one embodiment unfiltered alpha values used to represent character glyphs are stored in a glyph cache. To avoid repeated filtering of character glyphs, in another embodiment, character glyphs are padded along their vertical edges, filtered and then stored in the glyph cache.

Methods and apparatus for filtering and caching data representing images

Hardware acceleration of the rending and animation of characters that treat each pixel sub-component as a distinct luminance intensity source. A bit-map representation of the sub-component-oriented character is generated by using a single image sample to generate each pixel sub-component. This may be accomplished by, for example overscaling a representation of the character, placing the overscaled representation of the character on grid, and then assigning a luminance and possibly a transparency value to each grid position based on the property of the overscaled character at the grid position. The, the character is rendered by interfacing with a hardware graphic unit that perform the final rendering and animation of the character.

Hardware-enhanced graphics acceleration of pixel sub-component-oriented images

Methods and apparatus for displaying images, e.g., text characters, on display devices which have multiple separately controllable luminance elements per pixel are described. Multiple alpha values are generated per pixel, e.g., one per pixel sub-component. Filtering is then performed to generate a filtered alpha value for each pixel sub-component. The filtering operation uses as its input multiple alpha values, e.g., 5 per pixel. The alpha values used for the filtering operation may come from neighboring pixels. Accordingly, in the case where character glyphs are combined to form larger images, e.g., text strings, the filtering operation performed on glyph edge pixels depends on the content of a neighboring character glyph. In one embodiment unfiltered alpha values used to represent character glyphs are stored in a glyph cache. After caching, the unfiltered alpha values from multiple glyphs are combined and then the filtering operation is performed. To avoid repeated filtering of character glyphs, in another embodiment, character glyphs are padded along their vertical edges, filtered and then stored in the glyph cache. Glyphs are output from the cache as required and then combined with filtered alpha values corresponding to overlapping image portions being summed. As a result of the summing processes, correct filtered alpha values are generated along glyph edges for the combined image corresponding to multiple glyphs.

Method and apparatus for filtering and caching data representing images

The present invention provides for automatic placement of typographical features such as vertical stems or horizontal segments of a character on high contrast pixel sub-component boundaries as part of a rendering process that uses separately controllable pixel sub-components of pixels to represent different portions of the character. In order to identify the typographical features of the character that are to be aligned with high contrast pixel sub-component boundaries, topology of the character is analyzed at runtime. In display devices having vertical stripes of same-colored pixel sub-components, it has been found that character legibility is increased when the left edges of stems are aligned with high contrast boundaries between pixel sub-components. Processing time and resources are conserved by performing a partial, rather than a full, topological analysis of the character. For example, some font files include data structures that define the position of key control points associated with the character, thereby indicating where the stems or other typographical features are located, and the relationship between different typographical features.

An emboldened font is simulated from a regular font by moving the outline that describes the font along a vector normal to the direction of the outline a predetermined distance. A new emboldened location is calculated for each control point that defines the font outline. The new location for each control point is determined by calculating a vector perpendicular to the outline at the location of the control point. The control point is then moved a predetermined distance along the perpendicular vector. The predetermined distance controls how much emboldening is applied to the font. The greater the predetermined distance, the more emboldened the font will appear. By moving all of the control points that define a font outline a predetermined distance along a vector perpendicular to the outline, a new outline is created that defines the emboldened version of the font.

Method and apparatus for variable weight outline emboldening of scalable outline fonts

Techniques for improving the resolution of images (either analog images, analytic images, or images having a higher resolution than that of a display device) to be rendered on patterned displays. In one aspect of the present invention, an overscaling or oversampling process may accept analytic character information, such as contours for example, and a scale factor or grid and overscale or oversample the analytic character information to produce an overscaled or oversampled image. The overscaled or oversampled image generated has a higher resolution than the display upon which the character is to be rendered. Displaced samples of the overscaled or oversampled image are then combined (or filtered). An analytic image, such as a line drawing for example, may be applied to the oversampling/overscaling process as was the case with the character analytic image. However, since the analytic image may have different units than that of the character analytic image, the scale factor applied may be different. Since an ultra resolution image is already &ldquo;digitized&rdquo;, that is, not merely mathematically expressed contours or lines between points, it may be applied directly to a process for combining displaced samples of the ultra-resolution image to generate another ultra-resolution image (or an image with sub-pixel information). The functionality of the overscaling/oversampling process and the processes for combining displaced samples may be combined into a single step analytic to digital sub-pixel resolution conversion process.

Methods apparatus and data structures for enhancing the resolution of images to be rendered on patterned display devices

Image data processing and image rendering methods and systems whereby images are displayed on display devices having pixels with separately controllable pixel sub-components. Images, such as text characters, are displayed on a display device with at least some features being rendered with sub-pixel precision. The displayed advance width of a character displayed with sub-pixel precision is compatible with the advance width of the character if it had instead been displayed with a conventional full pixel precision rendering process. Thus, characters are displayed with sub-pixel precision, resulting in improved resolution and readability, while the advance width and the corresponding size and spacing of the characters and the overall formatting of the document remains the same compared to documents and characters rendered using conventional full pixel precision processes. The sub-pixel precision rendering process also involves mapping spatially different sets of one or more samples of the image data to individual pixel sub-components rather than to full pixels.

Rendering sub-pixel precision characters having widths compatible with pixel precision characters

Methods and systems for increasing the contrast with which thin-stemmed characters can be displayed in sub-pixel rendering processes are disclosed. Some fonts, such as Courier New, have relatively thin stems and other character features that would otherwise be rendered with low contrast when displayed using an oversampling process combined with a rendering process that treats individual pixel sub-components as separate luminous intensity sources. In order to avoid such low contrast features and to avoid the need for revising the font itself, the alpha values for the pixel sub-components that correspond to the character features are selectively increased to simulate larger dimensions of the character features and to increase the contrast with which the character dimensions are displayed. The methods involve oversampling image data representing a character by obtaining multiple samples for each of a plurality of pixel sub-components of a pixel. The alpha values associated with pixel sub-components at or near the position of the character features are increased to give the appearance of larger dimensions of the character features and greater contrast in the displayed image.

Adjusting character dimensions to compensate for low contrast character features

Methods and systems are disclosed for utilizing an increased number of samples of image data, coupled with the separately controllable nature of RGB pixel sub-components, to generate images with increased resolution on a display device. such as a liquid crystal display. The methods include scaling, hinting, and scan conversion operations. The scaling operation involves scaling the image data by factors of one in the directions perpendicular and parallel to the RGB striping of the display device. Hinting includes placing the scaled image data on a grid that has grid points defined by the positions of the pixels of the display device, and rounding key points to the nearest full pixel boundary in the direction parallel to the striping and to the nearest fractional increment in the direction perpendicular to the striping. Scan conversion includes scaling the hinted image data by an overscaling factor in the direction perpendicular to the striping. The overscaling factor is equivalent to the denominator of the fractional increments of the grid. Scan conversion also includes generating, for each region of the image data, a number of samples that equals the overscaling factor and mapping spatially different sets of the samples to each of the pixel sub-components.

Methods and systems for asymmeteric supersampling rasterization of image data

The widths of characters, that have had (or that are having) resolution enhancement processing applied, are adjusted so that the widths of the characters are maintained. In this way, formatting of any file including such characters is maintained. Specifically, the advance width of each character may be adjusted. A non-uniformity of gaps between characters may be minimized by adjusting the left and/or right side bearing of each character. Finally, a non-uniformity in the weight of character lines may be minimized by adjusting the black body width of each character.

Growing community of inventors

Redmond, WA, United States of America

Claude Betrisey