| 提交 | 用户 | 时间 | ||
| 58d006 | 1 | ## Frequently asked questions ## |
| A | 2 | |
| 3 | #### How much data can Flot cope with? #### | |
| 4 | ||
| 5 | Flot will happily draw everything you send to it so the answer | |
| 6 | depends on the browser. The excanvas emulation used for IE (built with | |
| 7 | VML) makes IE by far the slowest browser so be sure to test with that | |
| 8 | if IE users are in your target group (for large plots in IE, you can | |
| 9 | also check out Flashcanvas which may be faster). | |
| 10 | ||
| 11 | 1000 points is not a problem, but as soon as you start having more | |
| 12 | points than the pixel width, you should probably start thinking about | |
| 13 | downsampling/aggregation as this is near the resolution limit of the | |
| 14 | chart anyway. If you downsample server-side, you also save bandwidth. | |
| 15 | ||
| 16 | ||
| 17 | #### Flot isn't working when I'm using JSON data as source! #### | |
| 18 | ||
| 19 | Actually, Flot loves JSON data, you just got the format wrong. | |
| 20 | Double check that you're not inputting strings instead of numbers, | |
| 21 | like [["0", "-2.13"], ["5", "4.3"]]. This is most common mistake, and | |
| 22 | the error might not show up immediately because Javascript can do some | |
| 23 | conversion automatically. | |
| 24 | ||
| 25 | ||
| 26 | #### Can I export the graph? #### | |
| 27 | ||
| 28 | You can grab the image rendered by the canvas element used by Flot | |
| 29 | as a PNG or JPEG (remember to set a background). Note that it won't | |
| 30 | include anything not drawn in the canvas (such as the legend). And it | |
| 31 | doesn't work with excanvas which uses VML, but you could try | |
| 32 | Flashcanvas. | |
| 33 | ||
| 34 | ||
| 35 | #### The bars are all tiny in time mode? #### | |
| 36 | ||
| 37 | It's not really possible to determine the bar width automatically. | |
| 38 | So you have to set the width with the barWidth option which is NOT in | |
| 39 | pixels, but in the units of the x axis (or the y axis for horizontal | |
| 40 | bars). For time mode that's milliseconds so the default value of 1 | |
| 41 | makes the bars 1 millisecond wide. | |
| 42 | ||
| 43 | ||
| 44 | #### Can I use Flot with libraries like Mootools or Prototype? #### | |
| 45 | ||
| 46 | Yes, Flot supports it out of the box and it's easy! Just use jQuery | |
| 47 | instead of $, e.g. call jQuery.plot instead of $.plot and use | |
| 48 | jQuery(something) instead of $(something). As a convenience, you can | |
| 49 | put in a DOM element for the graph placeholder where the examples and | |
| 50 | the API documentation are using jQuery objects. | |
| 51 | ||
| 52 | Depending on how you include jQuery, you may have to add one line of | |
| 53 | code to prevent jQuery from overwriting functions from the other | |
| 54 | libraries, see the documentation in jQuery ("Using jQuery with other | |
| 55 | libraries") for details. | |
| 56 | ||
| 57 | ||
| 58 | #### Flot doesn't work with [insert name of Javascript UI framework]! #### | |
| 59 | ||
| 60 | Flot is using standard HTML to make charts. If this is not working, | |
| 61 | it's probably because the framework you're using is doing something | |
| 62 | weird with the DOM or with the CSS that is interfering with Flot. | |
| 63 | ||
| 64 | A common problem is that there's display:none on a container until the | |
| 65 | user does something. Many tab widgets work this way, and there's | |
| 66 | nothing wrong with it - you just can't call Flot inside a display:none | |
| 67 | container as explained in the README so you need to hold off the Flot | |
| 68 | call until the container is actually displayed (or use | |
| 69 | visibility:hidden instead of display:none or move the container | |
| 70 | off-screen). | |
| 71 | ||
| 72 | If you find there's a specific thing we can do to Flot to help, feel | |
| 73 | free to submit a bug report. Otherwise, you're welcome to ask for help | |
| 74 | on the forum/mailing list, but please don't submit a bug report to | |
| 75 | Flot. | |
