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Articles by Chandu yadav
Page 46 of 81
How can I change the value of an instance of a row in MySQL table?
UPDATE command along with WHERE clause can be used to change the value of an instance of a row. Basically, MySQL will change the value on the basis of the condition given in the query. Following example can demonstrate itSuppose we want to change the name from ‘Ram’ to ‘Mohit’ in the ‘testing’ table given below −mysql> Select * from testing; +----+---------+ | Id | Name | +----+---------+ | 1 | Harshit | | 2 | Lovkesh | | 3 | Ram | | 4 | Gaurav | +----+---------+ 4 rows in set (0.00 sec)Now ...
Read MoreHow does the compilation/linking process work in C/C++?
The compilation of a C++ program consists of three steps −Preprocessing − In simple terms, a C Preprocessor is just a text substitution tool and it instructs the compiler to do required pre-processing before the actual compilation. It handles preprocessing directives like #include, #define, etc.Compilation − The compilation takes place on the preprocessed files. The compiler parses the pure C++ source code and converts it into assembly code. This in turn calls the assembler that converts the assembly code to machine code(binary) as Object files. These Object files can refer to symbols that are not defined. The compiler won't give ...
Read MoreMake HTML5 Canvas fill the whole page
To make canvas fill the whole page, you need to be 100% in width and height of the page.* { margin: 0; padding: 0; } body, html { height:100%; } #canvas { position:absolute; height:100%; width:100%; }
Read MoreDoes HTML5 Canvas support Double Buffering?
For double buffering on the canvas, create a 2nd canvas element and draw to it. After that draw the image to the first canvas using the drawImage() method,// canvas element var canvas1 = document.getElementById('canvas'); var context1 = canvas1.getContext('2d'); // buffer canvas var canvas2 = document.createElement('canvas'); canvas2.width = 250; canvas2.height =250; var context2 = canvas2.getContext('2d'); // create on the canvas context2.beginPath(); context2.moveTo(10,10); context2.lineTo(10,30); context2.stroke(); //render the buffered canvas context1.drawImage(canvas2, 0, 0);
Read Moreimageconvolution() function in PHP
The imageconvolution() functionSyntaxbool imageconvolution (img, matrix, div, offset )Parametersimg: Create image with imagecreatetruecolor() function.matrix: A 3x3 matrix is an array of three arrays of three floats.div: Divisor of the result of the convolution, used for normalization.offset: The color offset.ReturnThe imageconvolution() function returns True on success or False on failure.ExampleThe following is an exampleOutputThe following is the outputExampleLet us see another example with different parameter values for the same image. You can easily spot the difference now:OutputThe following is the output
Read Moreimagecopymerge() function in PHP
The imagecopymerge() function copy and merge part of an image.Syntaximagecopymerge ( dst_img, src_img, dst_x, dst_y, src_x, src_y, src_w, src_h, pct )Parametersdst_im Set destination image link resource.src_im Set source image link resource.dst_x Set x-coordinate of destination point.dst_y Set y-coordinate of destination point.src_x Set x-coordinate of source point.src_y Set y-coordinate of source point.src_w Set source width.src_h Set source height.pct The two images will be merged according to pct which can range from 0 to 100.ReturnThe imagecopymerge() function returns the TRUE on success or FALSE on failure.ExampleThe following is an example:OutputThe following is the output displaying the merge of two images:ExampleLet us see ...
Read Moreimagechar() function in PHP
The imagechar() function draws a character horizontally.Syntaxbool imagechar( img, font, x, y, ch, color )Parametersimg: Creating an image with imagecreatetruecolor().font: Set font sizex: x-coordinatey: y-coordinatec: The character to draw.color: A color identifier created with imagecolorallocate().ReturnThe imagechar() function returns TRUE on success or FALSE on failure.ExampleThe following is an example:OutputThe following is the output:ExampleLet us see another example wherein we are drawing a character with different coordinates and height/ width as shown in the above example:OutputThe following is the output:
Read Moreimagecolorallocate() function in PHP
The imagecolorallocate() function allocates a color for an image.Syntaxint imagecolorallocate ( $img, $red, $green, $blue )Parametersimg: Image resource created with imagecreatetruecolor().red: Red color componentgreen: Green color componentblue: Blue color componentReturnThe imagecolorallocate() function returns a color in RGB format.ExampleThe following is an example:OutputThe following is the output:
Read Moreimagecreate() function in PHP
The imagecreate() function is used to create a new image. It is preferred to use imagecreatetruecolor() to create an image instead of imagecreate(). This is because the image processing occurs on the highest quality image possible which can be created using imagecreatetruecolor().Syntaximagecreate( $width, $height )Parameterswidth: The width of imageheight: The height of imageReturnThe imagecreate() function returns an image resource identifier on success or FALSE on errors.ExampleThe following is an example:OutputThe following is the output:
Read Morehighlight_file() function in PHP
The highlight_file() function outputs a file with the PHP syntax highlighted.Syntaxhighlight_file(file, return)Parametersfile − The file name to display.return − If this parameter is set to true, this function will return the highlighted code as a string, instead of printing it out. default is false.ReturnThe highlight_file() function returns the highlighted code as a string instead of printing it. Returns true on success, or false on failure, otherwise.ExampleThe following is an example, wherein we are using a test file ("new.php") to output the file with the PHP syntax highlighted. OutputThe output of the browser. ...
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