Abstract: Conditional determination of glyph substitution (GSUB) lookups or glyph positioning (GPOS) lookups in the process of rendering a string of text as a sequence of glyphs is described. A process can include receiving a string of text comprising a sequence of characters, obtaining a sequence of glyph identifiers (IDs) corresponding to the sequence of characters, and determining that a context of the string of text satisfies a condition. Based at least in part on the context satisfying the condition, an alternate lookup can be determined and executed in lieu of a default lookup. Execution of the alternate lookup causes a GSUB operation or a GPOS operation to be performed on the sequence of glyph IDs to ultimately cause the string of text to be rendered on a display as a sequence of glyphs with a typographical feature applied thereto.

Abstract: Various embodiments utilize a layout viewport and a visual viewport separate from the layout viewport. The layout viewport is utilized for such things as page layout operations and reporting Document Object Model values to script. The layout viewport can be thought of as an initial rectangle which is equivalent in size to the initial containing block. The initial containing block is a containing block that contains web content that is initially visible to the user. The visual viewport is separate from the layout viewport and is allowed to be freely manipulated relative to the layout viewport. For example, the visual viewport may “push” the layout viewport around when it collides with the layout viewport boundaries. The visual viewport can be thought of as the rectangle that is visible to the user.

Abstract: Techniques for synchronization points for state information are described. In at least some embodiments, synchronization points are employed to propagate state information among different processing threads. A synchronization point, for example, can be employed to propagate state information among different independently-executing threads. Accordingly, in at least some embodiments, synchronization points serve as inter-thread communications among different independently-executing threads.

Abstract: Techniques for synchronization points for state information are described. In at least some embodiments, synchronization points are employed to propagate state information among different processing threads. A synchronization point, for example, can be employed to propagate state information among different independently-executing threads. Accordingly, in at least some embodiments, synchronization points serve as inter-thread communications among different independently-executing threads.

Abstract: Various embodiments utilize a layout viewport and a visual viewport separate from the layout viewport. The layout viewport is utilized for such things as page layout operations and reporting Document Object Model values to script. The layout viewport can be thought of as an initial rectangle which is equivalent in size to the initial containing block. The initial containing block is a containing block that contains web content that is initially visible to the user. The visual viewport is separate from the layout viewport and is allowed to be freely manipulated relative to the layout viewport. For example, the visual viewport may “push” the layout viewport around when it collides with the layout viewport boundaries. The visual viewport can be thought of as the rectangle that is visible to the user.

Abstract: A character within a font is enlarged to a desired size by first determining whether the font contains existing or predefined variants of the character having the desired size. If no appropriately sized variant exists, the enlarged character is assembled from a plurality of component glyphs that are stored with the font, wherein the component glyphs include an extender that may be duplicated within the assembled character in order to achieve the desired size. In one embodiment, the font includes tables containing records of the enlarged variants for a particular character, as well as part records for the component glyphs used to assemble the enlarged character.

Abstract: A character within a font is enlarged to a desired size by first determining whether the font contains existing or predefined variants of the character having the desired size. If no appropriately sized variant exists, the enlarged character is assembled from a plurality of component glyphs that are stored with the font, wherein the component glyphs include an extender that may be duplicated within the assembled character in order to achieve the desired size. In one embodiment, the font includes tables containing records of the enlarged variants for a particular character, as well as part records for the component glyphs used to assemble the enlarged character.