Flex and Actionscript doesn’t handle TIFF images inherently. However, there is a library of TIFF decoding functions that I found buried in the interwebs (Big thanks to C.T. Yeung).
I made a few slight modifications because it wasn’t working when I downloaded it from Yeung. Speaking of which, this decoder doesn’t support TIFF compression. So you can’t load LZW or ZIP compressed TIFFs.
This code will show you how to create zoom functionality on your flex charts, as shown here: (click and drag on the chart to create the zoom window)
Before I get to the code, there’s a couple of notes:
You will notice that the data tips don’t show up, even if you enable showDataTips. This is a known bug, caused by disabling filterData on the chart series. filterData forces the chart to render all data points, even if they’re not shown on the current chart view. This is important, because if those points aren’t rendered, the chart doesn’t draw the lines that extend to those points.
If you’re worried that rendering unnecessary data points will cause performance issues, you can extend your series class and override the updateFilter method. You’ll need to rewrite it so that it excludes/includes the proper data points.
If you’re not worried about the effects of filterData, and you’d like a quick work-around for showing data tips, you’ll still need to extend your series class, but its a bit more simple. You just need to override findDataPoints with some minor adjustments, and add the private function formatDataTip. Here’s a link with the edited class: FilterLineSeries.as I copied the code directly from the LineSeries source, and made some minor adjustments.
[Bindable]privatevar profits:Array;
privatevar dragStart:Point;
privatevar dragEnd:Point;
privatevar zooming:Boolean;
// initializes the data provider with random dataprivatefunction init():void{
profits = newArray({month: 0, profit: 15});
for(var i:int=1; i<40; i++)
profits.push({month: i, profit: Math.round(Math.random()*25-10)+profits[i-1].profit});
}// sets the start point of the zoom windowprivatefunction startDraw(e:MouseEvent):void{
zooming = true;
dragStart = new Point(series1.mouseX, series1.mouseY);
}// draws the zoom window as your mouse movesprivatefunction showDraw(e:MouseEvent):void{if(zooming){
dragEnd = new Point(series1.mouseX, series1.mouseY);
// finds the top-left and bottom-right ponits of the zoom windowvar TL:Point = new Point(); // top-left pointvar BR:Point = new Point(); // bottom-right pointif(dragStart.x< dragEnd.x){
TL.x = dragStart.x;
BR.x = dragEnd.x;
}else{
TL.x = dragEnd.x;
BR.x = dragStart.x;
}if(dragStart.y< dragEnd.y){
TL.y = dragStart.y;
BR.y = dragEnd.y;
}else{
TL.y = dragEnd.y;
BR.y = dragStart.y;
}// prevents the zoom window from going off the canvasif(TL.x<0) TL.x = 0;
if(BR.x> chartCanvas.width-1) BR.x = chartCanvas.width-1;
if(TL.y<0) TL.y = 0;
if(BR.y> chartCanvas.height-1) BR.y = chartCanvas.height-1;
// draw the actual zoom window
chartCanvas.graphics.clear();
chartCanvas.graphics.lineStyle(1, 0x000000, 0.25);
chartCanvas.graphics.beginFill(0xd4e3f0,0.5);
chartCanvas.graphics.drawRect(TL.x, TL.y, BR.x-TL.x, BR.y-TL.y);
chartCanvas.graphics.endFill();
}}// clears the drawing canvas and sets the new max/minsprivatefunction finishDraw(e:MouseEvent):void{
zooming = false;
chartCanvas.clear();
// converts the drag coordinates into axis data pointsvar chartValStart:Array = chartCanvas.localToData(dragStart);
var chartValEnd:Array = chartCanvas.localToData(dragEnd);
// sets the new maximum and minimum for both axes
haxis.minimum = (chartValStart[0]< chartValEnd[0]) ? chartValStart[0] : chartValEnd[0];
haxis.maximum = (chartValStart[0]< chartValEnd[0]) ? chartValEnd[0] : chartValStart[0];
vaxis.minimum = (chartValStart[1]< chartValEnd[1]) ? chartValStart[1] : chartValEnd[1];
vaxis.maximum = (chartValStart[1]< chartValEnd[1]) ? chartValEnd[1] : chartValStart[1];
}// resets the axis max/minsprivatefunction resetZoom():void{
haxis.minimum = NaN;
haxis.maximum = NaN;
vaxis.minimum = NaN;
vaxis.maximum = NaN;
}
I know there seems to be a lot of unnecessary code in the showDraw function, but it serves a good purpose. Your user isn’t always going to start their zoom at the top-left corner and drag down to the bottom-right. The code distinguishes where the corners are, and draws the box accordingly.
EDIT (11/2/2010): Here’s how it would be done if you’re using a DateTimeAxis for your horizontal axis:
main.mxml:
(EDIT 8/14/09: In the SWF above, the sine wave is upside down. That’s because I had a typo when I wrote it. On line 7 of the code, I had typed “…yaxis + amp…” but it should be minus. The code above is correct, but the SWF hasn’t been updated)