|
ConvertSprite
The ConvertSprite module provides a proxy conversion for the ImageFileRender routines to the ImageFileConvert module. This means that the renderers provided by ImageFileRender can be be used as sources for a conversion to sprite. For example, the Artworks ImageFileRender is proxied by the ConvertSprite module so that an Artworks to Sprite conversion is possible.
In addition, the ConvertSprite module provides a means by which sprites can be created from an arbitrary rendering routine, in a similar manner to that used by the DragAnObject module.
SWIs
SWI ConvertSprite_CreateSprite
On entry
R0 = flags :
bit 0 = use mask
Others reserved
R1 = image width in OS units
R2 = image height in OS units
R3 = mode to use, or -1 for current
R4 = pointer to palette, or -1 for none, or unused for deep modes
R5 = pointer to sprite buffer, or 0 to read buffer size
R6 = size of sprite buffer
R7 = SWI number to call
R8 = pointer to 10 register block to pass to SWI
R9 = background colour
On exit
R6 = size of sprite buffer needed (if R5=0 on entry),
size of sprite buffer used (if R5<>0 on entry
This SWI is used to create a sprite of a given type using any arbitrary rendering routine. This allows clients to convert images which would usually be rendered to the screen to sprites.
Introduction
The ImageFileFileConvert module provides an interface for converting between different image formats through a simple defined interface. Whilst this interface may not be perfectly suited to all image formats, it can be extended through flagged operations to provide greater flexibility and to allow more functional conversions to be made.
Because ImageFileConvert and ImageFileRender complement one another it is recommended that users of either familiarise themselves with the other.
ImageFileConvert_Convert (&56840)
On entry
R0 = flags for operation :
bit 0-7 = Reserved for options common to output filetype
bits 8-15 = Reserved for options common to input filetype
bits 16-23 = Reserved for options specific to the input/output pair
bits 24-31 = Reserved
R1 = conversion requested :
bits 0-11 = Destination filetype
bits 12-15 = Reserved, must be 0
bits 16-25 = Source filetype
bits 26-31 = Reserved, must be 0
R2 = pointer to input image data
R3 = length of input image data
R4 = pointer to output image buffer, or 0 to read size
R5 = size of output image buffer, or 0 to read size
R6 = background colour, or -1 for default (may be ignored by some converters)
R7-R9 = passed to conversion process
On exit
R5 = size of output image buffer required, or -1 if not known (if R4 = 0 on entry),
size of output image buffer used (if R4 not 0 on entry)
This SWI is used to convert an image from one format to another.
Flags common to output type 'Sprite'
Because Sprite is a common type to convert to a number of flags are defined as being used for all conversions.
bit 0: Create a sprite, rather than a sprite file (this option is provided
by the ImageFileConvert module)
bit 1-7: Reserved
Flags common to output type 'JPEG'
Because JPEG is a common type to convert to a number of flags are defined as being used for all conversions.
bit 0: Output JPEG will be monochrome (otherwise it will be colour)
bit 1-3: Quality control :
0 = 75% (the default level)
1 = 12%
2 = 25%
3 = 37%
4 = 50%
5 = 62%
6 = 75%
7 = 88%
The duplication of 75% in both 0 and 6 is to allow users to leave the flags unset and get a sensible default conversion quality.
bit 4-7: Reserved
Flags common to input type 'Sprite'
Although sprite is a common filetype to convert from none of the flags are reserved for all conversions.
bit 8-15: Reserved
ImageFileConvert_MiscOp (&56841)
On entry
R0 = flag bits :
bits 0-7 = Reserved for options common to output filetype
bits 8-15 = Reserved for options common to input filetype
bits 16-23 = Reserved for options specific to the input/output pair
bits 24-31 = Reserved
R1 = conversion requested :
bits 0-11 = Destination filetype
bits 12-15 = Reserved, must be 0
bits 16-25 = Source filetype
biys 26-31 = Reserved, must be 0
R2 = pointer to input image data
R3 = length of input image data
R4 = operation type :
&000-&3FF Reserved for generic operations on all conversions
&400-&7FF Reserved for operations specific to the output type
&800-&BFF Reserved for operations specific to the input type
&C00-&FFF Reserved for operations specific to the input/output pair
Other, Reserved for future expansion
R5-R9 = misc op parameters
On exit
R0-R9 updated by conversion module
This SWI is used to provide miscellaneous operations to obtain information about the conversion process.
Operations common to the output type 'Sprite'
On entry
R4 = &400 (Read information)
R5-R9 undefined
On exit
R0 = width in pixels of image
R1 = height in pixels of image
R2 = bits per pixel in the image
R3 = image flags :
bit 0 = Image has a palette (if On exit 8bpp)
bit 1 = Image is colour (otherwise image is greyscale)
bit 2 = Image has alpha channel or mask
bits 3-5 = Interlace type:
0 = No interlacing
1 = Adam7 interlacing
2 = Vertical interlacing
Others Reserved
bits 6-31 Reserved
R4 = x DPI
R5 = y DPI
This operation reads information about the image which is common to most bitmap-type operations.
ImageFileConvert_Register (&56843)
On entry
R0 = flags (reserved, must be 0)
R1 = pointer to definition (all will be copied):
+0 API version (100)
+4 converter flags
bits 0-31 = Reserved, must be 0
+8 converter type :
bits 0-11 = Destination filetype
bits 12-15 = Reserved, must be 0
bits 16-25 = Source filetype
bits 26-31 = Reserved, must be 0
+12 pointer to name of converter in form :
<name><tab><version x.xx><tab><author>
+16 workspace value for r12
+20 pointer to conversion routine
+24 pointer to miscop routine
On exit
R1 = API version (even if an error occurs)
All other registers preserved
This SWI is used to register a new converter.
ImageFileConvert_Deregister (&56844)
On entry
R0 = flags (reserved, must be 0)
R1 = filetype pair
R2 = pointer to name to be copied in format :
<name><tab><version x.xx><tab><author>
On exit
All registers preserved
This SWI is used to deregister a converter.
ImageFileConvert_EnumerateConverters (&56845)
On entry
R0 = flags (reserved, must be 0)
R1 = last filetype pair, or -1 for the first call
On exit
R0 = pointer to renderer definition (read only)
R1 = this filetype pair, or -1 if no more
This SWI is used to enumerate the currently registered converters.
ImageFileConvert_ConverterInfo (&56846)
On entry
R0 = flags (reserved, must be 0)
R1 = filetype pair
On exit
R0 = pointer to renderer definition (read only)
R1 = pointer to renderer name
This SWI is used to read information on a conversion. If no conversion can be performed for the requested types, an error will be returned.
|
![[Select]](../imgs/seldoc.png)
