On Jan 14, 2014, at 5:43 AM, iMath <[email protected]> wrote: > if an image only contains gray colors, is there still any need to convert > it to a grayscale image? > BTW,I think an image only contains gray colors is a grayscale image.
There is a difference is how much space it takes up: 1 byte per pixel for a grayscale and 3 bytes per pixel for a color image that happens to be comprised of only shades of gray. And its been a little since I looked at it, but IIRC Qt has different functions between color and gray scale images. Certainly, palette based image objects have different functions. Tim Doty > > > ------------------ Original ------------------ > From: "Sean Fisk";<[email protected]>; > Date: Tue, Jan 14, 2014 11:09 AM > To: "iMath"<[email protected]>; > Cc: "pyside"<[email protected]>; > Subject: Re: [PySide] Does isGrayscale() can tell whether a color image > cansafely be converted to a grayscale image? > > I would presume that if an image only contains gray colors, it can be safely > converted to a grayscale image. Since allGray() and isGrayscale() indicate > the former, that would also mean they indicate the latter. > > > > -- > Sean Fisk > > > On Sun, Jan 12, 2014 at 6:21 AM, iMath <[email protected]> wrote: > In the Image Formats part of QImage doc says > " > The allGray() and isGrayscale() functions tell whether a color image can > safely be converted to a grayscale image. > " > but in the doc of there 2 functions indicate they're used to decide whether > an image is grayscale image ,not mentioned they could be used to tell whether > a color image can safely be converted to a grayscale image. > > what about your opinion ? > > _______________________________________________ > PySide mailing list > [email protected] > http://lists.qt-project.org/mailman/listinfo/pyside > > > _______________________________________________ > PySide mailing list > [email protected] > http://lists.qt-project.org/mailman/listinfo/pyside _______________________________________________ PySide mailing list [email protected] http://lists.qt-project.org/mailman/listinfo/pyside
