diff -r ebc84c812384 -r 46218c8b8afa Symbian3/PDK/Source/GUID-22E46647-D677-5A47-A7E0-E1E0AE736B27.dita --- a/Symbian3/PDK/Source/GUID-22E46647-D677-5A47-A7E0-E1E0AE736B27.dita Thu Mar 11 15:24:26 2010 +0000 +++ b/Symbian3/PDK/Source/GUID-22E46647-D677-5A47-A7E0-E1E0AE736B27.dita Thu Mar 11 18:02:22 2010 +0000 @@ -1,70 +1,70 @@ - - - - - -DirectGDI -Adaptation Overview -

The DirectGDI Adaptation component, together with the DirectGDI Interface -component, forms the DirectGDI adaptation layer. The DirectGDI Interface component -defines the interfaces that the adaptations must implement and the DirectGDI -Adaptation component consists of the two DirectGDI implementations that are -provided in the Graphics package.

-

Target audience: Device creators.

-DirectGDI is deprecated in Symbian^3. -

The DirectGDI component provides -a framework that enables graphics hardware acceleration and interleaved rendering. -This framework provides an API for client applications and a Hardware Adaptation -Interface (HAI), which defines interfaces that must be implemented by device -and hardware manufacturers in order to provide the API functionality. The -framework has a dependency on the Graphics -Resource Component.

-

The Graphics package includes two DirectGDI adaptations:

- -

The following diagram shows the generic DirectGDI API and implementation, -with one software and two hardware implementations. Although shown on the -same diagram, in fact only one implementation can exist on the same phone. -A configuration at ROM build time decides which implementation is used.

- - DirectGDI architecture - - -

Notice that all three of the implementations implement the common MDirectGdiEngine interface. -Also notice that the hardware implementation uses asynchronous calls to the -graphic acceleration hardware driver. This means that the CPU can continue -with other processing while the GPU is busy processing the rendering request. -This improves the parallelism between the CPU and the GPU.

-

The software implementation does not use asynchronous calls, because the -rendering is performed by the CPU.

-
Generic layer

The -following figure shows the classes in the DirectGDI generic layer (which is -shaded green). Classes that are provided by other components are shown in -red. Classes that cross the generic layer boundary have some parts that cannot -be modified (such as a fixed API), but have other parts that can be modified.

- The DirectGDI generic layer classes - -
- -DirectGDI -Component -DirectGDI -Interface Component -Creating -a DirectGDI Adaptation + + + + + +DirectGDI +Adaptation Overview +

The DirectGDI Adaptation component, together with the DirectGDI Interface +component, forms the DirectGDI adaptation layer. The DirectGDI Interface component +defines the interfaces that the adaptations must implement and the DirectGDI +Adaptation component consists of the two DirectGDI implementations that are +provided in the Graphics package.

+

Target audience: Device creators.

+DirectGDI is deprecated in Symbian^3. +

The DirectGDI component provides +a framework that enables graphics hardware acceleration and interleaved rendering. +This framework provides an API for client applications and a Hardware Adaptation +Interface (HAI), which defines interfaces that must be implemented by device +and hardware manufacturers in order to provide the API functionality. The +framework has a dependency on the Graphics +Resource Component.

+

The Graphics package includes two DirectGDI adaptations:

+
    +

  • A purely software adaptation +that uses existing components to draw to the screen in a similar manner to +BitGDI. This is suitable for use in phones that do not include graphics acceleration +hardware.

    • +

  • A hardware adaptation +that uses OpenVG and EGL APIs on the H4 platform. This is provided for reference +purposes and there is no requirement that the implementation use OpenVG. Hardware +manufacturers can in fact use any third-party rendering system that is suitable +for use with the target hardware.

    • +
+

The following diagram shows the generic DirectGDI API and implementation, +with one software and two hardware implementations. Although shown on the +same diagram, in fact only one implementation can exist on the same phone. +A configuration at ROM build time decides which implementation is used.

+ + DirectGDI architecture + + +

Notice that all three of the implementations implement the common MDirectGdiEngine interface. +Also notice that the hardware implementation uses asynchronous calls to the +graphic acceleration hardware driver. This means that the CPU can continue +with other processing while the GPU is busy processing the rendering request. +This improves the parallelism between the CPU and the GPU.

+

The software implementation does not use asynchronous calls, because the +rendering is performed by the CPU.

+
Generic layer

The +following figure shows the classes in the DirectGDI generic layer (which is +shaded green). Classes that are provided by other components are shown in +red. Classes that cross the generic layer boundary have some parts that cannot +be modified (such as a fixed API), but have other parts that can be modified.

+ The DirectGDI generic layer classes + +
+ +DirectGDI +Component +DirectGDI +Interface Component +Creating +a DirectGDI Adaptation \ No newline at end of file