(Removed the list of atoms, which is version specific. Instead, instruction was given to how to get the atoms.) |
m (Oops turns out the CAAtom structure is a bit more complex. Replaced the instruction with a tool.) |
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</source> | </source> | ||
The CAAtom of 0 always return <tt><nil></tt>, and that of an undefined atom is <tt><unknown></tt>. Custom atom's value are always larger than the built-in ones. | |||
== Tools == | |||
* [https://github.com/kennytm/Miscellaneous/blob/master/dump_caatom.py dump_caatom.py] — this script can dump internal CAAtom's from the QuartzCore binary. | |||
{{occlass|library=QuartzCore.framework|navbox=1}} | {{occlass|library=QuartzCore.framework|navbox=1}} | ||
Revision as of 22:15, 21 January 2011
CAAtom refers to a string for identification in QuartzCore. As of 3.1, there are over 300 internal atoms.
Converting atoms to and from strings
| Signature | NSString* CAAtomGetString(uint32_t atomicValue); |
|---|---|
| Available in | 2.0 – |
| Signature | uint32_t CAInternAtom(NSString* atommicString); |
|---|---|
| Available in | 2.0 – |
There is only 2 exported C function for CAAtom, CAAtomGetString() and CAInternAtom(), which converts between an integer and its corresponding string value. Most internal code in QuartzCore are identified using atoms. For example, a portion of disassembled code may read:
-[CAGradientLayer setLocations:]:
;
+00000 0008d9cc stmdb sp!,{r7,lr}
+00004 0008d9d0 add r7,sp,#0x0
+00008 0008d9d4 mov r1,#0xad
+0000c 0008d9d8 bl CALayer_setter_kCAValueCopiedPointer
+00010 0008d9dc ldmia sp!,{r7,pc} ; return
here, the magic number 0xAD is in fact an atom, which is unsurprisingly the value "locations":
cy# CAAtomGetString(0xad)
"locations"
The CAAtom of 0 always return <nil>, and that of an undefined atom is <unknown>. Custom atom's value are always larger than the built-in ones.
Tools
- dump_caatom.py — this script can dump internal CAAtom's from the QuartzCore binary.
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