xiaoDD

I would like to add some useful links to my previous messages. I guess I found the answer that DPI is NOT EQUAIVALENT to PPI (Pixels Per Inch). [Please refer to the following link: http://www.computerhope.com/jargon/p/ppi.htm] The definition of some useful video/image related terms can be found as follows: ---------- DPI: http://www.computerhope.com/jargon/d/dpi.htm or http://whatis.techtarget.com/definition/0,,sid9_gci213912,00.html Pixel: http://www.computerhope.com/jargon/p/pixel.htm or http://whatis.techtarget.com/definition/0,,sid9_gci212793,00.html Resolution: http://www.computerhope.com/jargon/r/resoluti.htm or http://whatis.techtarget.com/definition/0,,sid9_gci212895,00.html DOT Pitch: http://www.computerhope.com/jargon/d/dotpitch.htm or http://whatis.techtarget.com/definition/0,,sid9_gci211995,00.html ---------- If you refer to the definition of DOT Pitch, i.e. 'Distance between pixels on a computer display screen measured in millimeters' from http://www.computerhope.com/jargon/d/dotpitch.htm, DOT Pitch is monitor dependence. If you notice the specifications of different brands of monitor, you will find that DOT Pitch of them might be different from others. So, again, as mentioned by Divil, there is no FIXED value for how many pixels in a milimeter. Let's refer back the Microsoft Paint example given before. The value, i.e. 100 pixel = 3.31cm (1.23inches), is obtained when the screen resolution of my monitor is set to be '1024 by 768 pixels'. In this case, as shown in the Attributes window of MS Paint, the DPI is 81 x 81 dots per inch. Let's say now I set my screen resolution to be '800 by 600 pixels', the relationship between 'pixel & cm' or 'pixel & inch' becomes '100 pixel = 4.00cm' or '100 pixel = 1.58inches' respectively. For this case, the DPI is 64 x 64 dots per inch. The following sentences are quoted from http://whatis.techtarget.com/definition/0,,sid9_gci212895,00.html - Display resolution is not measured in dots per inch as it usually is with printers. However, the resolution and the physical monitor size together do let you determine the pixels per inch (and therefore, pixels per milimeter by doing little unit conversion). Typically, PC monitors have somewhere between 50 and 100 pixels per inch. For example, a 15-inch display modes monitor has a resolution of 640 pixels along a 12-inch horizontal line or about 53 pixels per inch. A smaller VGA display would have more pixels per inch. So, esteuart, I hope this could help ... TQvM

Hi, I agree with Divil that there is no FIXED value for 'for how many millimetres are in a pixel or vice versa'. By the way, Divil, how do you learn that the value of DPI (Dots Per Inch) that we are working with? Can I say that Dots Per Inch is EQUIVALENT to Pixels Per Inch? TQvM

Hi esteuart, Wait ... sorry ... I think I know which 'panel' that you talked about ... it's a control in VB .NET, right? Well ... I try to answer ... I guess you're using Windows XP. If that's the case, go to Start Menu -> Programs -> Accessories -> Paint. Once Paint is opened, click Image menu -> Attributes... Make sure that the option button of 'Pixels' is checked. Then type 100 for 'Width' and 100 for 'Height', and after that press 'OK'. You will see that page (by default, the color of the page should be white) shrinks to the size defined by the values of 'Width' and 'Height'. Again, you open the Attributes windows. This time, you check the option button of 'Cm'. Please note that the values in 'Width' and 'Height' will change automatically. Let's say the new value for 'Width' is 3.13, so it means that 100 pixels is equivalent to 3.13 cm or 31.3mm. For more detail, please read the attachment. TQvM

Hi In my opinion, it is possible to convert 'milimeter' to 'pixel' ... However, before I suggest the solution, I would like to understand few terms/phrases in your message. What do you mean: [1] panel [2] the size of panel in pixels [3] current resolution TQvM

Hi divil, Thanks a lot for your explanation. I appreciate it very much. TQvM

Hi, I wish to write a program using VB .NET for drawing/plotting a curve (e.g. squrewave, sinewave, line, etc). Would anyone please advise which control is suitable to perform this task? TQvM

Hi, Thanks for your comment. For your information, I'm using Windows XP Professional and have both Visual Studio 6.0 and Visual Studio .NET installed in my PC. I wrote the program in VS .NET and VS 6.0 as well. I found that ALT key of the program written using VS 6.0 worked fine (in Windows XP). But ALT key of the program written using VS .NET worked differently. If you say that 'This is the proper behaviour for all programs running on Windows 2000 or later. Keyboard accelerators are not displayed until the user hits the Alt key', why did the ALT key of the program written using VS 6.0 work immediately without requiring the user to hit the ALT key? Please advise. TQvM

I wrote a simple program using Visual Basic from Visual Studio .NET. The simple program had three buttons, i.e. Display, Clear and Exit. As you can see, different access keys had been assigned to the buttons, i.e. ALT+D for Display button, ALT+C for Clear button, and ALT+X for Exit button. No any further code was attached to the objects. Once the 'visual' programming part of the job was completed, I executed the program by selecting 'Start' (or by pressing F5). I found that NO UNDERLINED character appeared on each button in the executed program. In other words, for example, Display instead of Display was shown on 'Display' button. However, when I press 'ALT' key (only ONE key) on the keyboard, the UNDERLINED characters were appeared. Would anyone please advise why does the ALT key in program written using Visual Studion .NET act weird/differently? TQvM