Method and apparatus for rasterizing transparent page

A device for rasterizing a transparent page, comprising:

• a page description language interpreting unit configured to:
• interpret the transparent page to obtain graphic entities, transparency properties of the graphic entities, and profile information of the graphic entities;
• and
• divide the transparent page into a transparent area and a nontransparent area according to the transparency properties of the graphic entities;
• and
• a de-transparentizing unit configured to:
• identify, from the graphic entities, an overlapping graphic entity having an overlapping portion with the transparent area according to the profile information of the graphic entities;
• and
• divide the transparent area into a de-transparentizing area and an ultimate transparent area by using the graphic entities respectively having an overlapping portion with the transparent area,
• wherein the de-transparentizing unit is further configured to:
• generate a cell of the transparent area by using the overlapping graphic entity, the cell having a same graphic entity property;
• divide the transparent area into the de-transparentizing area and the ultimate transparent area according to a type of the cell;
• write an area covered by the cell into the de-transparentizing area if the cell is a first type of cell or a second type of cell;
• and
• write an area covered by the cell into the ultimate transparent area if the cell is a third type of cell,
• wherein:
• the first type of cell is a cell only containing graph-type graphic entities:
• the second type of cell is a cell only containing one image-type graphic entity or one shading-type graphic entity;
• the third type of cell is a cell at least containing two types of graphic entities or at least containing two image-type graphic entities or two shading-type graphic entities.

A non-transitory computer-readable storage medium with an executable program stored thereon, wherein the program, when executed by at least one processor, causes a computing device to perform operations comprising:

• interpreting the transparent page to obtain graphic entities, transparency properties of the graphic entities, and profile information of the graphic entities;
• dividing the transparent page into a transparent area and a nontransparent area according to the transparency properties of the graphic entities;
• identifying, from the graphic entities, an overlapping graphic entity having an overlapping portion with the transparent area according to the profile information of the graphic entities;
• and
• dividing the transparent area into a de-transparentizing area and an ultimate transparent area by using the overlapping graphic entity,
• wherein dividing the transparent area into a de-transparentizing area and an ultimate transparent area comprises:
• generating a cell of the transparent area by using the overlapping graphic entity, the cell having a same graphic entity property;
• dividing the transparent area into the de-transparentizing area and the ultimate transparent area according to a type of the cell;
• writing an area covered by the cell into the de-transparentizing area if the cell is a first type of cell or a second type of cell;
• and
• writing an area covered by the cell into the ultimate transparent area if the cell is a third type of cell,
• wherein:
• the first type of cell is a cell only containing graph-type graphic entities;
• the second type of cell is a cell only containing one image-type graphic entity or one shading-type graphic entity;
• the third type of cell is a cell at least containing two types of graphic entities or at least containing two image-type graphic entities or two shading-type graphic entities.