Hello, Rick Root wrote: > From this code: > > http://www.jhlabs.com/ip/BoxBlurFilter.java > > I'm interested in the following snippet: > > ta += ((rgb1 >> 24) & 0xff)-((rgb2 >> 24) & 0xff); > tr += ((rgb1 & 0xff0000)-(rgb2 & 0xff0000)) >> 16; > tg += ((rgb1 & 0xff00)-(rgb2 & 0xff00)) >> 8; > tb += (rgb1 & 0xff)-(rgb2 & 0xff); > > Here's the code I've written in CF. > > ta = ta + > BitAnd(BitSHRN(rgbRight,24),255)-BitAnd(bitSHRN(rgbLeft,24),255); > tr = tr + > BitSHRN(BitAnd(rgbRight,16711680)-BitAnd(rgbLeft,16711680),16); > tg = tg + BitSHRN(BitAnd(rgbRight,65280)-BitAnd(rgbLeft,65280),8); > tb = tb + BitAnd(rgbRight,255)-BitAnd(rgbLeft,255); > > Unfortunately, this isn't working. Either I've written the code wrong, > or the original code is wrong. I don't understand what it's doing at > all other than it's SUPPOSED to cause a blur by doing something with > pixels to the left and right of a given pixel. >
The concept is almost right, with a blur every pixel has a percentage of its adjacent pixels added into it so the simple sum indicated by the tb above is correct except that there is no percentage component. The sum should be in the form new_pixel = old_pixel + percentage_of_blur(left_pixel-Right_Pixel) but that is at the pixel level, not with the RGB components. If you do simple math like that component-by-component you get some very messy artifacts with the major contributor being that fact that the eye is non-linear in that space. You need to convert everything to Y/R-Y/B-Y, HSV or a similar coding so that the manipulation occur along the correct axes. Take a peek at: http://www.mbcomms.net.au/tools/ColourPicker1.cfm, grab a couple of colours and go to the "View Related Colours" page (button in lower right area of the first page, the design was based on the "squeeze as much as you can on the page" principle :-)) That page has a section lower down where graduations of colours take place, a blur in effect, quite smoothly. All of the maths behind that is HSV-based and works well. We got that code from the 'Net, credits given there somewhere, and I can pass it on if you wish.... HTH Kym K ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Create robust enterprise, web RIAs. Upgrade & integrate Adobe Coldfusion MX7 with Flex 2 http://ad.doubleclick.net/clk;56760587;14748456;a?http://www.adobe.com/products/coldfusion/flex2/?sdid=LVNU Archive: http://www.houseoffusion.com/groups/CF-Talk/message.cfm/messageid:263896 Subscription: http://www.houseoffusion.com/groups/CF-Talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=11502.10531.4
