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Real mouse position in canvas [duplicate]

....clientY - rect.top }; } Just call it from your event with the event and canvas as arguments. It returns an object with x and y for the mouse positions. As the mouse position you are getting is relative to the client window you'll have to subtract the position of the canvas element to convert...
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Sort rows in data.table in decreasing order on string key `order(-x,v)` gives error on data.table 1.

... Update data.table v1.9.6+ now supports OP's original attempt and the following answer is no longer necessary. You can use DT[order(-rank(x), y)]. x y v 1: c 1 7 2: c 3 8 3: c 6 9 4: b 1 1 5: b 3 2 6: b 6 3 7: a 1 4 8: a 3 5 9: a 6 6 ...
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'is' versus try cast with null check

...// only one cast if (myObjRef != null) { // myObjRef is already MyType and doesn't need to be cast again ... } C# 7.0 supports a more compact syntax using pattern matching: if (myObj.myProp is MyType myObjRef) { ... } ...
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How can I make a time delay in Python? [duplicate]

...l... it'll print less frequently than that, because it takes time to print and handle all the buffers that entails (possibly doing a kernel context switch), and to register the alarm signal, but... yeah. A little under once per minute. – Parthian Shot Jun 17 '1...
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Remove last character from C++ string

...is to use the function that is intended for this task, it's called erase() and the code is: st.erase(st.size()-1). This would be called a "mutating version". – Czarek Tomczak Jan 19 '13 at 14:46 ...
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What's the difference between F5 refresh and Shift+F5 in Google Chrome browser?

What's the difference between F5 refresh and SHIFT + F5 in Google Chrome browser? 3 Answers ...
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How do I check if a variable exists in a list in BASH

...amp; echo 'yes' || echo 'no'. it's correct assuming space is the separator and $x doesn't contain space – Tianren Liu Apr 5 '16 at 21:47 ...
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How to get all possible combinations of a list’s elements?

I have a list with 15 numbers in, and I need to write some code that produces all 32,768 combinations of those numbers. 27...
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Unable to import a module that is definitely installed

... I have run into this many times and I think I just discovered the reason: umask is passed through sudo, so if your personal umask is tight and you use sudo for the install, the files and directories will be over-restricted. If you simply su first and then...
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How can I send an inner to the bottom of its parent ?

The div inside another div picture and code below. Because there will be text and images of the parent div. And red div will be the last element of the parent div. ...