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Analysis of rendering labels on other sites
Now the merkalt sites (excluding wallstickers) are using the next schemz: after the customer changed label parameters (type the text on the lines and leave the field; select motif, background or text color) there is a lock of all controls of product and execution of script in the background which renders label. The rendering result is saved in a temporary image file. In the HTML the label's preview is defined as the “image” html-element which URL linked with the rendered image file.
Update performed after each character set in the lines fields of the label preview constructor. On each change of solitary character, delayed update is started (timeout is 500 ms). After each click (color changing, motif selecting, etc.) the label update started without a pause. When update of label preview is ready, it applied unless user made any other action - this case the change not applied and preview generation starts again. Label's image URL is not the link to the updated image file as it now on Merkalt. There is an URL to script which generates label image and returns the image. Each user action launches a change of parameters for image URL and then receives updated image. For example, after typing text “text” in the Linje 1 generates URL to preview image as /extensions/ColorStickers/operations.php?&operation=preview&bk=undefined&g=0&rand=7113.364054360752&c=000000&l1=test&l2=&l3=&f=1 for preview. If we change the color of the text to blue the URL will be /extensions/ColorStickers/operations.php?&operation=preview&bk=undefined&g=0&rand=5381.829658103297&c=0c75eb&l1=test&l2=&l3=&f=1. There is changed parameter “c”. By changing label preview URL parameters they gets new label preview.
A similar algorithm for rendering the label as in the previous case. The only difference is that the process takes place without timeout.
There are div elements as container for the label. All changes made by the user are displayed directly in the container html markup using javascript. This method is used on the merkalt's wallstickers site now. The advantages of this method is that the whole process of rendering labels are on the client side, no server requests are performed and therefore there is no need to use lockers or calls rendering by timeout as preview change is immediate. The disadvantage of this method is that it need much more work. This method is one of the best in terms of performance. Perhaps it could be considered to be used.
The principle of label rendering is similar to the previous case