Today I was helping someone who was wanting to write a script to take screen-shots from one application and then paste those screen-shots into Microsoft Excel. <\/p>\n
Initially things weren’t working reliably because the script didn’t factor in the time taken for the large bitmap of a screen-shot to exist in the clipboard after pressing the print screen button, before attempting to paste into Excel. E.g. consider:<\/p>\n
Press Print Screen\r\nSetFocus>Microsoft - Excel*\r\nPress CTRL\r\nSend>v\r\nRelease CTRL<\/pre>\nThe above is probably going to fail most of the time because a screen shot is a large bitmap and is going to take some time to arrive on the clipboard, but the script above performs a paste in Excel immediately after pressing print screen. The print screen key being depressed and the clipboard containing the bitmap are not the same thing.<\/p>\n
While we could have just said “wait 5 seconds” and that would probably have been fine for evermore, it isn’t very sensitive and wouldn’t be ideal for a script that needs to run as fast as possible. Ideally we only want to wait until we know the bitmap is in the clipboard.<\/p>\n
Text is usually smaller than a bitmap, but for large text items one way to make things bulletproof is to do something like this:<\/p>\n
PutClipBoard>dummy\r\n\r\nSetFocus>source_app_title\r\nPress CTRL\r\nSend>c\r\nRelease CTRL\r\n\r\nLabel>wait_for_data\r\nWait>0.2\r\nGetClipBoard>clipdata\r\nIf>clipdata=dummy\r\n Goto>wait_for_data\r\nEndif<\/pre>\nBy putting a known value onto the clipboard in the first place we can then have a little loop which keeps checking the clipboard until the returned value is not our known value. We then know our CTRL-V has worked and that we can safely paste to the target application.<\/p>\n
But how can we do the same thing when the clipboard data is an image? The above won’t work because GetClipBoard won’t return anything for non-textual data. <\/p>\n