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This article mainly shows you "WeChat Mini Programs development how to use canvas to draw coordinate maps", the content is easy to understand, clear, hope to help you solve your doubts, the following let the editor lead you to study and learn "WeChat Mini Programs development how to use canvas to draw coordinate maps" this article.

1. Line graph

Function draw (data, ctx) {var width, height = 300,ratioX, ratioY, maxY, stepY; var newArr = new Array (); / /-data processing-if (data.time = = null) {return;} if (data.type = = 'day' | | data.type = =' month') {var timeList = new Array (); for (var I = 0; I < data.time.length) If ((I% 4 = = 0 & & data.type = = 'day') | | (I% 5 = = 0 & & data.type = =' month')) {timeList.push (data.time.substr (data.timeI] .length-5,5));}} data.time = timeList;} else {for (var I = 0; I < data.time.length) Data.time +) {success [I] = data.time.substr (data.time.length-5,5);} / / the data returned by the background is displayed on the page / /-get the screen width-wx.getSystemInfo ({success: function (res) {width = res.windowWidth). }}) ratioX = parseInt ((width-60) / (data.time.length-1)); ratioY = parseInt ((height-45) / 6); / / find the maximum value of value for (var I = 0; I < data.list.length; ifold +) {newArr.push (Math.max.apply (Math, data.list [I] .value));} maxY = Math.max.apply (Math, newArr); stepY = Math.ceil (maxY / 4) / /-draw coordinate lines-ctx.beginPath (); for (var I = 0; I < 5; iTunes +) {ctx.save (); ctx.setStrokeStyle ("# dde2e3"); ctx.setFillStyle ("# 848198"); ctx.setFontSize ('8'); ctx.fillText (I * stepY, 0220-I * ratioY); ctx.moveTo (22,215-I * ratioY) Ctx.lineTo ((width-30), 215-I * ratioY); ctx.stroke (); ctx.restore ();} /-draw a legend-for (var I = 0; I < data.list.length; I +) {ctx.save (); ctx.translate (15215); ctx.beginPath (); ctx.setStrokeStyle (color [I]) Ctx.setLineCap ("round"); ctx.setLineWidth (10); ctx.moveTo (22 + I * 38,46); ctx.lineTo (38 + I * 38,46); ctx.stroke (); ctx.setFontSize ('8'); ctx.setFillStyle ("# 000000"); ctx.fillText (data.list.title, 21 + I * 38,66); ctx.restore () } / /-draw Abscissa-for (var I = 0; I < data.time.length; I +) {ctx.save (); ctx.translate (15215); ctx.setFontSize ('8'); ctx.setFillStyle ('# 848198'); ctx.fillText (data.time [I], I * (ratioX), 20); ctx.restore () } /-draw broken lines-for (var I = 0; I < data.list.length; iTunes +) {ctx.beginPath (); ctx.save (); ctx.translate (22,215); ctx.setStrokeStyle (color [I]); ctx.moveTo (0,-data.list [I] .value [0] / (stepY / ratioY)); / / console.log (data.list.value) For (var j = 0; j < data.list [I] .value.length; jacks +) {ctx.lineTo (j * (parseFloat ((width-53) / (data.list [I] .value.length-1)),-(data.list.value [j] / (stepY / ratioY); ctx.stroke ();} ctx.restore ();} ctx.draw ();}

2. Pie chart

Function draw (data, ctx) {var start = 0Power0, end,width; var ratio = new Array (); wx.getSystemInfo ({success: function (res) {width = res.windowWidth;}}); x = width / 2-15; for (var item0)

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