Comments for iOS/Web Developer's Life in Beta http://nachbaur.com Making broken software somewhat less broken Tue, 10 Jan 2012 23:24:35 +0000 hourly 1 http://wordpress.org/?v=3.3.1 Comment on Core Graphics isn’t scary, honest! by Vladimir Grichinahttp://nachbaur.com/blog/core-graphics-isnt-scary-honest/comment-page-1#comment-1464 Vladimir Grichina Tue, 10 Jan 2012 23:24:35 +0000 http://nachbaur.com/?p=724#comment-1464 Note that you can also use [UIColor set], [UIColor setFill] and [UIColor setStroke] to set drawing color in a simpler way. Note that you can also use [UIColor set], [UIColor setFill] and [UIColor setStroke] to set drawing color in a simpler way.

]]> Comment on Core Graphics isn’t scary, honest! by Michael Nachbaurhttp://nachbaur.com/blog/core-graphics-isnt-scary-honest/comment-page-1#comment-1174 Michael Nachbaur Thu, 05 Jan 2012 19:17:46 +0000 http://nachbaur.com/?p=724#comment-1174 Hi Jean, as Paul commented up above, my post has a few bugs in its code samples, so I need to fix that. Hi Jean, as Paul commented up above, my post has a few bugs in its code samples, so I need to fix that.

]]> Comment on Core Graphics isn’t scary, honest! by Michael Nachbaurhttp://nachbaur.com/blog/core-graphics-isnt-scary-honest/comment-page-1#comment-1173 Michael Nachbaur Thu, 05 Jan 2012 19:17:02 +0000 http://nachbaur.com/?p=724#comment-1173 Thank you for catching those bugs in my post. I wrote this from memory without having access to Xcode or the Xcode documentation over the Christmas holidays, so I obviously missed a few steps. I'll update the post ASAP to fix these bugs. Again, thanks! Thank you for catching those bugs in my post. I wrote this from memory without having access to Xcode or the Xcode documentation over the Christmas holidays, so I obviously missed a few steps.

I’ll update the post ASAP to fix these bugs. Again, thanks!

]]> Comment on Core Graphics isn’t scary, honest! by Jeanhttp://nachbaur.com/blog/core-graphics-isnt-scary-honest/comment-page-1#comment-1172 Jean Thu, 05 Jan 2012 12:37:23 +0000 http://nachbaur.com/?p=724#comment-1172 Hi I have tried to run the code uilabel drawing with the second drawRect. However, drawRect is not called, even when I use [self setNeedsDisplay]. Hi
I have tried to run the code uilabel drawing with the second drawRect. However, drawRect is not called, even when I use [self setNeedsDisplay].

]]> Comment on Core Graphics isn’t scary, honest! by Paulhttp://nachbaur.com/blog/core-graphics-isnt-scary-honest/comment-page-1#comment-1169 Paul Wed, 04 Jan 2012 15:18:36 +0000 http://nachbaur.com/?p=724#comment-1169 I think it's great that you are putting effort in introducing newcomers to CoreGraphics but in this post beginners will pick up some things they probably should not be picking up. The docs for -[UILabel drawTextInRect:] state the following: "You should not call this method directly. This method should only be overridden by subclasses that want to modify the default drawing behavior for the label’s text." Doing what you do in your code samples is ill-advised in terms of future-proofing your application. Apart from that there is no -[UIViewController drawRect:], so the code sample will not work and will probably add to the confusion among beginners about the role of UIViewController and UIView. I think it’s great that you are putting effort in introducing newcomers to CoreGraphics but in this post beginners will pick up some things they probably should not be picking up.

The docs for -[UILabel drawTextInRect:] state the following:

“You should not call this method directly. This method should only be overridden by subclasses that want to modify the default drawing behavior for the label’s text.”

Doing what you do in your code samples is ill-advised in terms of future-proofing your application.

Apart from that there is no -[UIViewController drawRect:], so the code sample will not work and will probably add to the confusion among beginners about the role of UIViewController and UIView.

]]> Comment on Core Graphics isn’t scary, honest! by Michael Nachbaurhttp://nachbaur.com/blog/core-graphics-isnt-scary-honest/comment-page-1#comment-1168 Michael Nachbaur Tue, 03 Jan 2012 06:09:37 +0000 http://nachbaur.com/?p=724#comment-1168 Yeah, I didn't want this post to be too long, so I intentionally avoided diving into too much detail there. To answer your questions: 1) I didn't use floorf because I wanted to round the values up (using ceilf). There are cases where rounding down is preferred. For example, in an application I'm working on right now I need to render borders between different UIView subclasses, and the left/right borders need to line up. I have to use ceilf on one side and floorf on the other, so that number values are rounded up or down so the borders don't overlap. 2) The reason I subtracted 0.5 from the Y coordinate, but not the X coordinate, was because the line I was showing here was a horizontal line that extended along the entire width of the view. In a follow-up post I'll provide some visuals to help explain this point more. Yeah, I didn’t want this post to be too long, so I intentionally avoided diving into too much detail there.

To answer your questions:

1) I didn’t use floorf because I wanted to round the values up (using ceilf). There are cases where rounding down is preferred. For example, in an application I’m working on right now I need to render borders between different UIView subclasses, and the left/right borders need to line up. I have to use ceilf on one side and floorf on the other, so that number values are rounded up or down so the borders don’t overlap.

2) The reason I subtracted 0.5 from the Y coordinate, but not the X coordinate, was because the line I was showing here was a horizontal line that extended along the entire width of the view. In a follow-up post I’ll provide some visuals to help explain this point more.

]]> Comment on Core Graphics isn’t scary, honest! by Michael Nachbaurhttp://nachbaur.com/blog/core-graphics-isnt-scary-honest/comment-page-1#comment-1167 Michael Nachbaur Tue, 03 Jan 2012 06:02:59 +0000 http://nachbaur.com/?p=724#comment-1167 If the labels are static, you might as well use Core Graphics to render the labels (either using a UILabel or direct rendering with NSString, whichever makes the most sense for you). As long as you don't need to re-layout your labels, and if you're able to take advantage of the contentMode property enough, you'll most likely never end up re-drawing that label much. So it'll be blazing fast. If the labels are static, you might as well use Core Graphics to render the labels (either using a UILabel or direct rendering with NSString, whichever makes the most sense for you). As long as you don’t need to re-layout your labels, and if you’re able to take advantage of the contentMode property enough, you’ll most likely never end up re-drawing that label much. So it’ll be blazing fast.

]]> Comment on Core Graphics isn’t scary, honest! by Scotthttp://nachbaur.com/blog/core-graphics-isnt-scary-honest/comment-page-1#comment-1166 Scott Mon, 02 Jan 2012 18:10:16 +0000 http://nachbaur.com/?p=724#comment-1166 Your pixel drawing example could use much more detail. You mention floorf and then never use it. You subtract .5 from one of the Y positions, but not the other. Why? Why don't you subtract it from the X coordinates too? Your pixel drawing example could use much more detail. You mention floorf and then never use it. You subtract .5 from one of the Y positions, but not the other. Why? Why don’t you subtract it from the X coordinates too?

]]> Comment on Core Graphics isn’t scary, honest! by Julien Vignalihttp://nachbaur.com/blog/core-graphics-isnt-scary-honest/comment-page-1#comment-1165 Julien Vignali Mon, 02 Jan 2012 13:08:37 +0000 http://nachbaur.com/?p=724#comment-1165 Great article with some good tips! I am playing with UILabel drawing and was wondering if drawing about 20 labels in a UIView is faster and more memory-friendly than managing 20 UILabels objects (note: the text of the labels are static, they won't change). What's your opinion ? And what about using NSString -drawInRect: method instead of UILabel's ? Does it make any difference ? Thanks :) Great article with some good tips!
I am playing with UILabel drawing and was wondering if drawing about 20 labels in a UIView is faster and more memory-friendly than managing 20 UILabels objects (note: the text of the labels are static, they won’t change).
What’s your opinion ?
And what about using NSString -drawInRect: method instead of UILabel’s ? Does it make any difference ?
Thanks :)

]]> Comment on Back To Basics: Simple debugging tips in Xcode by Nick Hopkinshttp://nachbaur.com/blog/basics-xcode-debugging-tips/comment-page-1#comment-1161 Nick Hopkins Thu, 29 Dec 2011 20:57:12 +0000 http://nachbaur.com/?p=726#comment-1161 Hi, Just like to day thanks for the Google logo fix for translucent toolbars over Google Maps - worked a treat! Nick Hi,
Just like to day thanks for the Google logo fix for translucent toolbars over Google Maps – worked a treat!
Nick

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