World Coordinates

From 7b52cc13af4e85f1ca2deb6b6c77de9c95ea0dcf Mon Sep 17 00:00:00 2001 From: scuri Date: Fri, 17 Oct 2008 06:10:33 +0000 Subject: First commit - moving from LuaForge to SourceForge --- html/en/func/wd.html | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 html/en/func/wd.html (limited to 'html/en/func/wd.html') diff --git a/html/en/func/wd.html b/html/en/func/wd.html new file mode 100644 index 0000000..9c83ec5 --- /dev/null +++ b/html/en/func/wd.html @@ -0,0 +1,80 @@ + + + + World Coordinates + + + + + +

World Coordinates

Allows the use of a World Coordinate System. In this system you can attribute + coordinates to any unit you want. After you define a window (rectangular + region) in your world, each given coordinate is then mapped to canvas + coordinates to draw the primitives. You can define a viewport in your canvas to + change the coordinate mapping from world to canvas. The image below shows the + relation between Window and Viewport.

Window x Viewport
+

If you want to map coordinates from one system to another, use the wdWorld2Canvas + e wdCanvas2World functions. +

The quality of the picture depends on the conversion from World to Canvas, so + if the canvas has a small size the picture quality will be poor. To increase + picture quality create a canvas with a larger size, if possible.

All World Coordinate drawing in all drivers are simulated using other CD + primitives.

void wdCanvasWindow(cdCanvas* canvas, double xmin, double xmax, double ymin, double ymax); [in C]
+    
+canvas:wWindow(xmin, xmax, ymin, ymax: number) [in Lua]

Configures a window in the world coordinate system to be used to convert world + coordinates (with values in real numbers) into canvas coordinates (with values + in integers). The default window is the size in millimeters of the whole + canvas.

void wdCanvasGetWindow(cdCanvas* canvas, double *xmin, double *xmax, double *ymin, double *ymax); [in C]
+
+canvas:wGetWindow() -> (xmin, xmax, ymin, ymax: number) [in Lua]

Queries the current window in the world coordinate system being used to + convert world coordinates into canvas coordinates (and the other way round). It + is not necessary to provide all return pointers, you can provide only the + desired values.

void wdCanvasViewport(cdCanvas* canvas, int xmin, int xmax, int ymin, int ymax); [in C]
+
+canvas:wViewport(xmin, xmax, ymin, ymax: number) [in Lua]

Configures a viewport in the canvas coordinate system to be used to convert + world coordinates (with values in real numbers) into canvas coordinates (with + values in integers). The default viewport is the whole canvas (0,w-1,0,h-1). + If the canvas size is changed, the viewport will not be automatically updated. +

void wdCanvasGetViewport(cdCanvas* canvas, int *xmin, int *xmax, int *ymin, int *ymax); [in C]
+
+canvas:wGetViewport() -> (xmin, xmax, ymin, ymax: number) [in Lua]

Queries the current viewport in the world coordinate system being used to + convert world coordinates into canvas coordinates (and the other way round). It + is not necessary to provide all return pointers, you can provide only the + desired values and NULL for the others.

void wdCanvasWorld2Canvas(cdCanvas* canvas, double xw, double yw, int *xv, int *yv); [in C]
+
+canvas:wWorld2Canvas(xw, yw: number) -> (xv, yv: number) [in Lua]

Converts world coordinates into canvas coordinates. It is not necessary to + provide all return pointers, you can provide only the desired values and NULL + for the others.

void wdCanvasCanvas2World(cdCanvas* canvas, int xv, int yv, double *xw, double *yw); [in C]
+
+canvas:wCanvas2World(xv, yv: number) -> (xw, yw: number) [in Lua]

Converts canvas coordinates into world coordinates. It is not necessary to + provide all return pointers, you can provide only the desired values and NULL + for the others.

Extra

void wdCanvasHardcopy(cdCanvas *canvas, cdContext* ctx, void *data, void(*draw_func)(cdCanvas *canvas_copy)); [in C]
+
+canvas:wCanvasHardcopy(ctx: number, data: string or userdata, draw_func: function) [in Lua]

Creates a new canvas, prepares Window and Viewport according to + the provided canvas, maintaining the aspect ratio and making the drawing occupy + the largest possible area of the new canvas, calls the drawing function (which + must use routines in WC) and, finally, removes the new canvas.

It is usually used for "hard copies" of drawings (print equivalent copy). The + most common used contexts are Printer, PS and PDF.

+ + -- cgit v1.2.3