Ability to visualize colors

[ZevEisenberg]

If I run visualize someColor, I get:

UIDeviceRGBColor isn't supported. You can visualize UIImage, CGImageRef, UIView, CALayer or NSData.

Chisel should generate a square or circular image of the color, optionally with some RGB/hex info included in the image, and open the image in Preview.

[ZevEisenberg]

Reference: when you Quick Look a color in the variables list:

[kastiglione]

Nice. Can I interest you in trying a pull request 😄

[ZevEisenberg]

Definitely interested. I’ll put it on my list for my job’s semi-weekly hack days.

[kastiglione]

Let me know if you have any questions, happy to answer anything.

[ZevEisenberg]

@kastiglione would it be a faux pas to expr @import CoreFoundation in my command? I'm trying to have it be able to differentiate between UIColor, CIColor, and CGColor (and maybe NSColor?)

[ZevEisenberg]

Specifically:

result = frame.EvaluateExpression('(CFTypeID)CFGetTypeID({color}) == (CFTypeID)CGColorGetTypeID()'.format(color=color))

[kastiglione]

would it be a faux pas to expr @import CoreFoundation in my command?

Nah. In fact I think it would be great to do, UIKit too. Thinking aloud, I wonder if it could be done on the first time any breakpoint is hit. Then by using Chisel, you get these for free.

[kastiglione]

Not to give you scope creep, feel free to put it in your command only. Someone can look to make it more general later.

[ZevEisenberg]

I've seen it advised to always import UIKit on an exception breakpoint. I had put a UIKit import in my ~/.lldbinit, but it seemed to slow down Xcode every time I started a debugging session. I'll try again some time.

Current question: here's an error I'm getting in lldb:

error: cannot initialize a parameter of type 'CGColor *' with an rvalue of type 'CGColorRef' (aka 'CGColor *')

From a python line like this:

colorToUse = '[UIColor colorWithCGColor:(CGColorRef){}]'.format(color)

Seen anything like this?

[ZevEisenberg]

Or, to simplify the question, what is the right way to call this in lldb?

po [UIColor colorWithCGColor:(CGColorRef)[[UIColor redColor] CGColor]]

[kastiglione]

Cast the color to void *?

[ZevEisenberg]

Nope:

(lldb) po [UIColor colorWithCGColor:(void *)[[UIColor redColor] CGColor]]
error: cannot initialize a parameter of type 'CGColor *' with an rvalue of type 'void *'
error: 1 errors parsing expression

(assuming that's what you meant?)

[kastiglione]

Yup, that is what I meant. Hmm. Maybe one of:

po [UIColor colorWithCGColor:(id)[[UIColor redColor] CGColor]]
po [UIColor colorWithCGColor:(CGColor *)[[UIColor redColor] CGColor]]
po [UIColor colorWithCGColor:(CGColor *)(void *)[[UIColor redColor] CGColor]]

[kastiglione]

Oh, I'm curious why you're going from UIColor to CGColor to UIColor?

[ZevEisenberg]

Just a simple test case to reproduce what I’m seeing in the script with a CGColor. I didn’t have a CGColor handy in an app, so I was making one from a UIColor in the debugger. If I can make a CGColor in code and reference it in the script and it works, I guess I will ignore this issue for now as an edge case. I’ll try that, and your suggestions.

[ZevEisenberg]

None of the suggestions worked, but worse, the actual case I'm trying to use also doesn't work. If I'm on a breakpoint and I have a local variable, cgColor, of type CGColorRef:

(lldb) po cgColor
<CGColor 0x7fdfa0546910> [<CGColorSpace 0x7fdfa0643f70> (kCGColorSpaceDeviceRGB)] ( 0 0.478431 1 1 )

(lldb) po [UIColor colorWithCGColor:cgColor]
error: cannot initialize a parameter of type 'CGColor *' with an lvalue of type 'CGColorRef' (aka 'CGColor *')
error: 1 errors parsing expression
(lldb) po [UIColor colorWithCGColor:(id)cgColor]
error: cannot initialize a parameter of type 'CGColor *' with an rvalue of type 'id'
error: 1 errors parsing expression
(lldb) po [UIColor colorWithCGColor:(CGColorRef)cgColor]
error: cannot initialize a parameter of type 'CGColor *' with an rvalue of type 'CGColorRef' (aka 'CGColor *')
error: 1 errors parsing expression
(lldb) po [UIColor colorWithCGColor:(CGColor *)cgColor]
error: use of undeclared identifier 'CGColor'
error: expected expression
error: 2 errors parsing expression
(lldb) po [UIColor colorWithCGColor:(struct CGColor *)cgColor]
error: cannot initialize a parameter of type 'CGColor *' with an rvalue of type 'struct CGColor *'
error: 1 errors parsing expression
(lldb) expr @import CoreGraphics
(lldb) po [UIColor colorWithCGColor:(struct CGColor *)cgColor]
error: cannot initialize a parameter of type 'CGColor *' with an rvalue of type 'struct CGColor *'
error: 1 errors parsing expression

So I can't use it in my script because it doesn't even work in the real debugger, at least not with the incantations I'm using.

[ZevEisenberg]

It looks like this is maybe already done in chisel? Does this code work? https://github.com/facebook/chisel/blob/master/commands/FBAutoLayoutCommands.py#L44

lldb.debugger.HandleCommand('expr (void)[%s setBorderColor:(CGColorRef)[(id)[UIColor %sColor] CGColor]]' % (layer, color))

[ZevEisenberg]

@kastiglione alright, I got a workaround thanks to @jvisenti: http://stackoverflow.com/a/31810890/255489

I believe it's related to the UIColor going out of scope, and -CGColor returning an internal pointer:

@property(nonatomic,readonly) CGColorRef CGColor;
- (CGColorRef)CGColor NS_RETURNS_INNER_POINTER CF_RETURNS_NOT_RETAINED;

PR should be in at some point soon-ish