// Usage: // (1) Call 'startxy()' once (e.g. from BODY onload="..") to start this code. // (2) Assumes that these Image dependent variables have already been defined: // // GifFileName = "??.gif"; // Km = nn; // Standard 64km, 128km, 256km or 512km radar picture. // ----------------------------------------------------------------- // // This code assumes a TABLE with a radar image and X, Y outputs, etc, // and then does the logic of updating X & Y whenever the mouse moves. if (nImages>0) { // Compute some internal globals. var maxKm = Km-1; // 128km is .5 KmPerPixel, 512km is 2 KmPerPixel var KmPerPixel = Km/256; // Internal Global variables. var xx=0; var yy=0; var zz=0; var aa=0; var xKm=0; var yKm=0; var xKmOrigin=0; var yKmOrigin=0; } // startxy is called once after the BODY has been loaded. // It initalises x-y stuff and sets up mouse-event-callbacks. // function startxy () { // Setup mouse-move & mouse-click(down) callbacks. if (isMS) { document.body.onmousemove=move; document.body.onmousedown=down; //document.animation.src = GifFileName; } if (isNN4) { document.captureEvents(Event.MOUSEMOVE); document.onMouseMove=move; document.captureEvents(Event.MOUSEDOWN); document.onMouseDown=down; //window.onresize = resize; // Not needed because the loop will reload it. //document.animationlayer.document.animation.src = GifFileName; } resetOrigin (); } // Netscape-only (maybe Xterms only), reload the image after a resize. function resize () { document.animationlayer.document.animation.src = GifFileName; } function move(e) // When the mouse moves, update the pointer boxes. { if (isMS) { e = window.event; // X-Y relative to the container (i.e. the image). xKm=9999 yKm=9999 if (e.srcElement && e.srcElement.name) { if (e.srcElement.name == "animation") { // 2003-03-11 reduce +2 to +1. xPixels = window.event.offsetX-262+1 yPixels = window.event.offsetY-262+1 // Mac IE forgets to adjust for the scroll bars. if (isMac) { xPixels += document.body.scrollLeft yPixels += document.body.scrollTop } xKm= xPixels*KmPerPixel yKm=-yPixels*KmPerPixel } } } if (isNN4) { xKm=9999 yKm=9999 if (e.target.name) { if (e.target.name == "animation") { xKm= (e.pageX-document.animationlayer.pageX-262+1)*KmPerPixel yKm=-(e.pageY-document.animationlayer.pageY-262+1)*KmPerPixel } } } if (Math.abs(xKm)>maxKm || Math.abs(yKm)>maxKm) { document.myForm.x.value="" document.myForm.y.value="" document.myForm.z.value="" document.myForm.a.value="" } else { xx=xKm-xKmOrigin yy=yKm-yKmOrigin zz=Math.round(Math.sqrt(xx*xx+yy*yy)-.01) aa=450-Math.round(Math.atan2(yy,xx)*57.29) if (aa>359) { aa=aa-360 } if (zz<1) { aa="0" } xx=Math.round(xx) yy=Math.round(yy) // Turn -0 into +0 if (xx == 0) { xx=0; } if (yy == 0) { yy=0; } if (zz == 0) { zz=0; } if (xx>=0) document.myForm.x.value = xx + ' km East' else document.myForm.x.value =-xx + ' km West' if (yy>=0) document.myForm.y.value = yy + ' km North' else document.myForm.y.value =-yy + ' km South' document.myForm.z.value = zz + ' km Away' document.myForm.a.value = aa + ' Degrees' } } function down() // A left-click (mouse-down) to move the Origin. { // xKm & yKm are the distances from the centre of the radar image. // They were already computed in (mouse) move() above. // (or are zero at startup.) // Maybe set the new origin. if (Math.abs(xKm)=0) document.offsets.xo.value = Math.round(xKmOrigin) + ' km East' else document.offsets.xo.value = -Math.round(xKmOrigin) + ' km West' if (yKmOrigin>=0) document.offsets.yo.value = Math.round(yKmOrigin) + ' km North' else document.offsets.yo.value = -Math.round(yKmOrigin) + ' km South' } function resetOrigin () { xKm = 0; yKm = 0; down (); } // Empty function - used to deal with image buttons rather than HTML buttons function xynullfunc() { } //-->