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diff --git a/html/en/canvas.html b/html/en/canvas.html new file mode 100644 index 0000000..dc7721b --- /dev/null +++ b/html/en/canvas.html @@ -0,0 +1,47 @@ +<html> + +<head> +<meta http-equiv="Content-Language" content="en-us"> +<link rel="stylesheet" type="text/css" href="../style.css"> +<title>Canvas</title> +</head> + +<body> + +<h1>Canvas</h1> + + <p>The canvas represents the drawing surface. It could be anything: a file, a + client area inside a window in a Window System, a paper used by a printer, + etc. Each canvas has its own attributes. </p> + <h3>Initialization</h3> + <p>You must call <b>cdCreateCanvas</b> to create a canvas, and <b>cdKillCanvas</b> when you do not need the canvas anymore. + It is not necessary to activate + a canvas using <b>cdCanvasActivate</b>, but some drivers may require that + call. </p> + <p>To know if a feature is supported by a driver, use function + <strong>cdContextCaps</strong> or see the driver's + documentation.</p> + <h3>Control</h3> + <p>Some canvases are buffered and need to be flushed; for that, use the <b>cdCanvasFlush</b> function. In some drivers, this function can also be used to + change to another page, as in drivers <b>CD_PRINTER</b> and <b>CD_PS</b>. + </p> + <p>You can clear the drawing surface with the <b>cdCanvasClear</b> function, + but in some drivers the function may just draw a rectangle using the + background color. </p> + <h3>Coordinate System</h3> + <p>You may retrieve the original canvas size using the <b>cdCanvasGetSize</b> + function. The canvas' origin is at the bottom left corner of the canvas, but + an origin change can be simulated with function <b>cdCanvasOrigin</b>. Usually + user interface libraries have their origin at the upper right corner, oriented + top down. In this case, the function <strong>cd</strong><b>Canvas</b><strong>UpdateYAxis</strong> + converts the Y coordinate from this orientation to CD's orientation and + vice-versa. </p> + <h3>Other</h3> + <p>Some canvas contents can be interpreted; the <b>cdCanvasPlay</b> function + interprets the contents of a canvas and calls library functions for the + contents to be displayed in the active canvas. </p> + + +</body> + +</html> |