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 300 dpi charts |
| Posted by Mikhail Fridman on Feb-04-2003 00:27 |
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I am using ChartDirector to generate all kids of charts. I need to produce two files. One for web at 72pdi and the other at 300 pdi for printing.
Can any one please tell me how to save charts to files with different resolution.
Thanks in advance |
| Re: 300 dpi charts |
| Posted by Peter Kwan on Feb-04-2003 03:04 |
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Hi Mikhail,
Unluckily, as ChartDirector outputs charts in PNG/GIF/JPEG format, it does not have the concept of dpi (or pdi). The charts are measured using "number of pixels" as unit.
By printing at "300 dpi", there are several methods.
1. If you want a chart to be 3 inches in width, then you can just create a chart as 900 pixels in width. Using this method, if you need both 72 dpi and 300 dpi, you have to create two charts with different sizes.
2. You can just print the original 72 dpi chart image using 300 dpi. This is actually a more common method. For example, the charts in all ChartDirector PDF documentation are screen resolution charts (you can call it 72 dpi if you like), but you can print the documentation using 300 dpi printer, and the resulting quality is still quite good (try it!). Simlarily, if you view any web page on a browser, the images are at screen resolution, but you can still print them on a 300 dpi printer. If you accept this method, there is no need to produce a separate 300 dpi chart image.
Regards
Peter Kwan |
| Re: 300 dpi charts |
| Posted by Dave on Apr-03-2009 00:46 |
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Hi Peter,
Has this functionality been added yet? I am also very interested in it.
Your point that you can make a bigger image and shrink it to be at 300dpi is not really true. If you did this, you'd have to rescale all fonts, control the number of ticks for each axis and many other similar styling things. At this point you're losing a lot of value of ChartDirector which makes intelligent choices on these issues. You're also making it almost impossible for someone producing charts based on run-time data.
Also your point of 'you can just print it using 300 dpi' is also not valid. The reason for a print-quality image is to ... well, have print quality. 72 dpi will look grainy and pixellated. And if this is being output to an electronic format where the user is expected to zoom in if they need, then the image will look blocky and unprofessional.
I'm sure a fair number of your customers end up having their charts used in marketing and promotional materials. So, this does seem like a really helpful feature to have.
Dave |
| Re: 300 dpi charts |
| Posted by Peter Kwan on Apr-03-2009 03:25 |
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Hi Dave,
You are absolutely correct that to increase the chart size, you need to increase the size of everything (the font size, tick density, etc). If the tick density is rescaled as well (using Axis.setTickDensity), ChartDirector can still choose the proper number of labels on the axis. I have seen people doing it in real applications. The result is quite good, but it does need more code.
Printing 72 dpi using 300 dpi will not cause the picture to become more grainy. It will cause the picture to become smaller in physically size and less grainy . For example, if the picture is 720 pixels wide, and you print it at 72 dpi, it will be 10 inches wide. If you print it at 300 dpi, it will be 2.4 inches wide.
If you have used a digital camera before, you may notice that if you print the photo on paper in a very large size (say 30 x 20 inches), the photo will become grainy. If you print the photo in a small size (3 x 2 inches), it will not be grainy. The photo or camera does not really have a fixed resolution in dpi (they only have pixel count). It depends on how you print it. The same applies to the charts.
Anyway, ChartDirector currently cannot automatically increase the number of pixels. Our current focus is on vertor graphics output, so the output becomes resolution independent. ChartDirector Ver 5.0 now supports SVG output. We may add more formats in future versions of ChartDirector.
Hope this can help.
Regards
Peter Kwan |
| Re: 300 dpi charts |
| Posted by James Moberg on Oct-23-2009 03:50 |
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I understand what you are saying in this thread and my question is somewhat related.
I'm generated graphs that are viewable on a webpage. I'm using Adobe ColdFusion's CFDocument tag to generate multi-page PDF reports from the generated HTML and images. In order to get nice looking images in a PDF, I usually make all images much larger than the visual space required.
Is there anyway to increase the scale of the chart's workspace prior to saving it so that the tick marks, font sizes, addText() blocks, etc don't have to all be manually refactored? The charts I have created look great on a webpage, but I need some way to increase the overall dimensions of the the chart when saving so that text doesn't look jagged when embedded in a PDF. |
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