Canon Kabushiki Kaisha

Scott Bradley

Stephen Edward Ecob

Timothy Merrick Long

Cameron Murray Edwards

Albert Chang

Michael Jan Lawther

Bin Liao

Benjamin Michael Lever

A method of compositing a plurality of graphic objects with a compositing buffer, is disclosed. The plurality of graphic objects forming a group is attenuated by group opacity and is composited from a top object to a bottom object. Based on a first mask and the group opacity, a second mask is generated. The first mask stores a remaining possible contribution for further graphic objects below and including the plurality of graphic objects. The plurality of graphic objects in a top down order is processed. In particular, for each graphic object of the plurality of graphic objects: (a) a contribution value for the graphic object using the second mask is determined, the contribution value representing a contribution of the graphic object to the compositing buffer; (b) a colour value of the graphic object is composited with the compositing buffer using the contribution value; and (c) the second mask is updated using the contribution value. The first mask is then updated using the second mask and the group opacity. The updated first mask is configured for further compositing of objects below the plurality of graphic objects.

Method of compositing variable alpha fills supporting group opacity

A method of rendering a scan line of a graphic object image in a scan line renderer for spans of pixels laying between consecutive x-ordered edges intersecting the scan line includes maintaining a set of depths present in the rendering of the scan line, with the set being maintained in depth order. For each span, the set contains at least those depths that are active in the span, and the set is subject to removal of at least one depth at a subsequent span on the scan line where the corresponding depth is no longer active.

Method for tracking depths in a scanline based raster image processor

Disclosed is an imaging engine system () generally intended for the reproduction of graphical object images using apparatus having limited computing resources, such as so-called 'thin clients'. Numerous developments of traditional image processing and rendering enable high quality image generation. One such development takes advantage of temporal coherence between one frame in an animation sequence and the succeeding frame. In particular, there will often be some edges () of graphical objects that remain 'static' across several contiguous frames. One example of this includes those edges used to draw image background detail. Another development performs antialiasing during scan line rendering of a graphic object image where sub-pixel resolution coverage bit-masks (A-buffers-) are generated for a limited number of scan lines at a time. Preferably the A-buffers are generated for only one pixel at a time. Another development relates to rendering a scan line of a graphic object image in a scan line renderer for a span of pixels lying between two x-order consecutive edges intersecting the scan line. For the span of pixels, this development maintains a subset of depths present in the rendering, the subset being those depths that are present on the span and being maintained in depth order () and subject to removal of depths where the corresponding depth is no longer active. In another development a compositing stack (-) of image layers to be rendered in a raster scan fashion is simplified. Rendering is operable over a run of two or more pixels within which a relationship between graphical objects contributing to the layers does not change. The layers are first divided into groups (), with each group being separated by a layer having variable transparency (). For a top one of the groups, layers having constant color in the run are reduced to a single equivalent color () having an associated accumulated contribution. Many other developments are disclosed.

Compositing with a sub-pixel mask in graphic object rendering

Disclosed is an imaging engine system () generally intended for the reproduction of graphical object images using apparatus having limited computing resources, such as so-called 'thin clients'. Numerous developments of traditional image processing and rendering enable high quality image generation. One such development takes advantage of temporal coherence between one frame in an animation sequence and the succeeding frame. In particular, there will often be some edges () of graphical objects that remain 'static' across several contiguous frames. One example of this includes those edges used to draw image background detail. Another development performs antialiasing during scan line rendering of a graphic object image where sub-pixel resolution coverage bit-masks (A-buffers) are generated for a limited number of scan lines at a time. Preferably the A-buffers are generated for only one pixel at a time. Another development relates to rendering a scan line of a graphic object image in a scan line renderer for a span of pixels lying between two x-order consecutive edges intersecting the scan line. For the span of pixels, this development maintains a subset of depths present in the rendering, the subset being those depths that are present on the span and being maintained in depth order () and subject to removal of depths where the corresponding depth is no longer active. In another development a compositing stack () of image layers to be rendered in a raster scan fashion is simplified. Rendering is operable over a run of two or more pixels within which a relationship between graphical objects contributing to the layers does not change. The layers are first divided into groups (), with each group being separated by a layer having variable transparency (). For a top one of the groups, layers having constant colour in the run are reduced to a single equivalent colour () having an associated accumulated contribution. Many other developments are disclosed.

Growing community of inventors

Fife, United Kingdom

Scott Bradley