CLASS CanvasScale (Defined in: jpgraph_canvtools.php : 25)

CanvasScale
CanvasScale() Set() Translate() TranslateX() TranslateY()

Class usage and Overview
This class defines a scale which is meant to be used with canvas graphs to make it possibles to pecify a more convinient scale compared to absoilute pixels coordinates.
This will also let you scale the canvas without any coordinate changes.

Class Methods

function CanvasScale(&$graph,$xmin,$xmax,$ymin,$ymax)
Define a scale for canvas graphs

Argument | Default | Description
--- | --- | ---
&$graph |  | Canvas graph
$xmin | 0 | Min X-value for scale
$xmax | 10 | Max X-value for scale
$ymin | 0 | Min Y-value for scale
$ymax | 10 | Max Y-value for scale

Description
Define a scale for canvas graphs. Note the scale values is optionally in this call. The may be later set witha call to the Set() method.
See also
CanvasScale::Set

function Set($xmin,$xmax,$ymin,$ymax)
Specify scale to use

Argument | Default | Description
--- | --- | ---
$xmin | 0 | Min X value
$xmax | 10 | Max X-value
$ymin | 0 | Min Y-value
$ymax | 10 | Max Y-value

Description
SPecify min/max values for scale.

Example

// Setup a basic canvas we can work
$g = new CanvasGraph(400,200,'auto');
$g->SetMargin(5,11,6,11);
$g->SetShadow();
$g->SetMarginColor("teal");
// We need to stroke the plotarea and margin before we add the
// text since we otherwise would overwrite the text.
$g->InitFrame();
// Create a new scale
$scale = new CanvasScale($g);
$scale->Set(0,$xmax,0,$ymax);

function Translate($x,$y)
Translate a point to absolute screen coordinates

Argument | Default | Description
--- | --- | ---
$x |  | X-value
$y |  | Y-value

Description
Translate a point to absolute screen coordinates
See also
CanvasScale::TranslateX and CanvasScale::TranslateY

Example

list($xt,$yt) = $scale->Translate($x,$y);
$graph->img->Point($xt,$yt);

function TranslateX($x)
Translate X-coordinate

Argument | Default | Description
--- | --- | ---
$x |  | X-value

Description
Translate X-value into absolute screen coordinates
See also
CanvasScale::Translate

function TranslateY($y)
Translate Y-value to absolute screen coordinates

Argument | Default | Description
--- | --- | ---
$y |  | Y-value

Description
Translate Y-value to absolute screen coordinates
See also
CanvasScale::Translate