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/coordinates.html | 148 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 148 insertions(+) create mode 100644 html/en/func/coordinates.html (limited to 'html/en/func/coordinates.html') diff --git a/html/en/func/coordinates.html b/html/en/func/coordinates.html new file mode 100644 index 0000000..9f119bb --- /dev/null +++ b/html/en/func/coordinates.html @@ -0,0 +1,148 @@ + + + + + + +Coordinate System + + + + + +

Coordinate System

+
void cdCanvasGetSize(cdCanvas* canvas, int *width, int *height, double *width_mm, double *height_mm); [in C]
+
+canvas:GetSize() -> (width, height, mm_width, mm_height: number) [in Lua]
+ +

Returns the canvas size in pixels and in millimeters. You can provide only + the desired values and NULL for the others.

+ +
int cdCanvasUpdateYAxis(cdCanvas* canvas, int *y); [in C]
+double cdfCanvasUpdateYAxis(cdCanvas* canvas, double *y); [in C]
+int cdCanvasInvertYAxis(cdCanvas* canvas, int y); [in C]
+double cdfCanvasInvertYAxis(cdCanvas* canvas, double y); [in C]
+
+canvas:UpdateYAxis(yc: number) -> (yr: number) [in Lua]
+canvas:InvertYAxis(yc: number) -> (yr: number) [in Lua]
+ +

In some graph systems, the origin is at the upper left corner of the + canvas, with the direction of the Y axis pointing down. In this case, the + function converts the coordinate system of the CD library into the internal + system of the active canvas' driver, and the other way round. If this is not + the case, nothing happens. This is just "y = height-1 - + y". It returns the changed value. The "Invert" will always invert + the given value, the "Update" function will invert only if the canvas has the + Y axis inverted.

+ +
void cdCanvasMM2Pixel(cdCanvas* canvas, double mm_dx, double mm_dy, int *dx, int *dy); [in C]
+void cdfCanvasMM2Pixel(cdCanvas* canvas, double mm_dx, double mm_dy, double *dx, double *dy); [in C]
+
+canvas:MM2Pixel(mm_dx, mm_dy: number) -> (dx, dy: number) [in Lua]
+canvas:fMM2Pixel(mm_dx, mm_dy: number) -> (dx, dy: number) [in Lua]
+ +

Converts sizes in millimeters into pixels (canvas coordinates). You can + provide only the desired values and NULL for the + others.

+ +
void cdCanvasPixel2MM(cdCanvas* canvas, int dx, int dy, double *mm_dx, double *mm_dy); [in C]
+void cdfCanvasPixel2MM(cdCanvas* canvas, double dx, double dy, double *mm_dx, double *mm_dy); [in C]
+
+canvas:Pixel2MM(dx, dy: number) -> (mm_dx, mm_dy: number) [in Lua]
+canvas:fPixel2MM(dx, dy: number) -> (mm_dx, mm_dy: number) [in Lua]
+ +

Converts sizes in pixels (canvas coordinates) into millimeters. You can + provide only the desired values and NULL for the + others. Use this function to obtain the horizontal and vertical resolution of + the canvas by passing 1 as parameter in dx and + dy. The resolution value is obtained using the + formula res=1.0/mm.

+ +
void cdCanvasOrigin(cdCanvas* canvas, int x, int y); [in C]
+void cdfCanvasOrigin(cdCanvas* canvas, double x, double y); [in C]
+
+canvas:Origin(x, y: number) [in Lua]
+canvas:fOrigin(x, y: number) [in Lua]
+ +

Allows translating the origin - for instance, to the center of the canvas. + The function profits from the architecture of the library to simulate a + translation of the origin, which in fact is never actually passed to the + canvas in the respective driver. Default values: (0, 0)

+ + +
void cdCanvasGetOrigin(cdCanvas* canvas, int *x, int *y); [in C]
+void cdfCanvasGetOrigin(cdCanvas* canvas, double *x, double *y); [in C]
+
+canvas:GetOrigin() -> (x, y: number) [in Lua]
+canvas:fGetOrigin() -> (x, y: number) [in Lua]
+ +

Returns the origin.

+ + +

Transformation Matrix

+ +
void cdCanvasTransform(cdCanvas* canvas, const double* matrix); [in C]
+
+canvas:Transform(matrix: table) [in Lua]
+ +

Defines a transformation matrix with 6 elements. If the matrix is NULL, + the + transformation is reset to the identity. Default value: NULL.

+

The matrix contains scale, rotation and translation elements as follows:

+ 
|x'|   |sx*cos(angle)    -sin(angle)  dx|   |x|                     |0   2   4| 
+|y'| = |   sin(angle)  sy*cos(angle)  dy| * |y|      with indices   |1   3   5|
+                                            |1|
+

But notice that the indices are different of the + cdCanvasVectorTextTransform.

+

Functions that retrieve images from the canvas are not affected by the +transformation matrix, such as GetImage, GetImageRGB +and ScrollArea.

+

Transformation matrix is independent of the World Coordinate +and Origin +functions. And those are affected if a transformation is set, just like other +regular primitives.

+ + +
double* cdCanvasGetTransform(cdCanvas* canvas); [in C]
+
+canvas:GetTransformation() -> (matrix: table) [in Lua]
+ +

Returns the transformation matrix. If the identity is set, returns NULL.

+ + +
void cdCanvasTransforMultiply(cdCanvas* canvas, const double* matrix); [in C]
+
+canvas:TransformMultiply(matrix: table) [in Lua]
+ +

Left multiply the current transformation by the given transformation.

+ +
void cdCanvasTransformTranslate(cdCanvas* canvas, double dx, double dy); [in C]
+
+canvas:TransformTranslate(dx, dy: number) [in Lua]
+ +

Applies a translation to the current transformation.

+ +
void cdCanvasTransformScale(cdCanvas* canvas, double sx, double sy); [in C]
+
+canvas:TransformScale(sx, sy: number) [in Lua]
+ +

Applies a scale to the current transformation.

+ +
void cdCanvasTransformRotate(cdCanvas* canvas, double angle); [in C]
+
+canvas:TransformRotate(angle: number) [in Lua]
+ +

Applies a rotation to the current transformation. Angle is in degrees, + oriented counter-clockwise from the horizontal axis.

+ +
void cdCanvasTransformPoint(cdCanvas* canvas, int x, int y, int *tx, int *ty); [in C]
+void cdfCanvasTransformPoint(cdCanvas* canvas, double x, double y, double *tx, double *ty); [in C]
+
+canvas:TransformPoint(x, y: number) -> (tx, ty: number) [in Lua]
+canvas:fTransformPoint(x, y: number) -> (tx, ty: number) [in Lua]
+ +

Applies a transformation to a given point.

+ + + + \ No newline at end of file -- cgit v1.2.3