lines

I am using using HTML5 Canvas to plot lines. A single line is formed by calling drawLine() on multiple intermediate points. For example: (0,0) -> (10, 10) -> (10, 5) -> (20, 12) would show up as one line on the plot. All the (x,y) co-ordinates of a line are stored in an array. I want to provide the users with the ability to select a line when they click on it. It becomes difficult to do this in HTML5 Canvas as the line is not represented by an object. The only option that I am left with is to first find that (x,y) coordinate of any line that is closest to the (x,y) of a mousedown event. Once I

I have a really simple QListWidget object and I want to build a folder list. When I add an item to my list here is what I do : void LessCC::on_addFolderButton_clicked() { QString dirName = QFileDialog::getExistingDirectory(this, tr("Choose Directory"), QDir::homePath(), QFileDialog::ShowDirsOnly); QListWidgetItem* newItem = new QListWidgetItem(QIcon(":/resources/icons/folder.png"), dirName, 0, 0); this->ui->folderListWidget->addItem(newItem); } This is working but I want my items to have multiple lines or column of informations (with different style). I heard about the QStyledItemDelegate but

While looking around for a while I found quite a few discussions on how to figure out the number of lines in a file. For example these three: c# how do I count lines in a textfile Determine the number of lines within a text file How to count lines fast? So, I went ahead and ended up using what seems to be the most efficient (at least memory-wise?) method that I could find: private static int countFileLines(string filePath) { using (StreamReader r = new StreamReader(filePath)) { int i = 0; while (r.ReadLine() != null) { i++; } return i; } } But this takes forever when the lines themselves from

I have two versions of a program that does basically the same thing, getting the biggest length of a line in a file, I have a file with about 8 thousand lines, my code in C is a little bit more primitive (of course!) than the code I have in C++. The C programm takes about 2 seconds to run, while the program in C++ takes 10 seconds to run (same file I am testing with for both cases). But why? I was expecting it to take the same amount of time or a little bit more but not 8 seconds slower! my code in C: #include <stdio.h> #include <stdlib.h> #include <string.h> #if _DEBUG #define DEBUG_PATH "..

I'm working on an implementation of the tail function and I'm only supposed to use read() , write() and lseek() for I/O, and so far I have this: int printFileLines(int fileDesc) { char c; int lineCount = 0, charCount = 0; int pos = 0, rState; while(pos != -1 && lineCount < 10) { if((rState = read(fileDesc, &c, 1)) < 0) { perror("read:"); } else if(rState == 0) break; else { if(pos == -1) { pos = lseek(fileDesc, 0, SEEK_END); } pos--; pos=lseek(fileDesc, pos, SEEK_SET); if (c == '\n') { lineCount++; } charCount++; } } if (lineCount >= 10) lseek(fileDesc, 2, SEEK_CUR); else lseek(fileDesc, 0,