Hi, On Thu, Dec 05, 2002 at 06:09:57PM +0100, Henning Meier-Geinitz wrote: > http://www.meier-geinitz.de/sane/sane2/
|4.5.2 Scan Resolution Options http://www.meier-geinitz.de/sane/sane2/0.07/doc014.html#s4.5.2 | Option resolution is used to select the resolution at which an image | should be acquired. When the backend wants to allow different values | for x- and y-resolution it has to define the options x_resolution and | y_resolution. Note that only the option resolution or the options | x_resolution and y_resolution may be active. "... may be active at the same time" to make it more clear. The option names are "x-resolution" and "y-resolution", aren't they? The underscore is not allowed in the name. | 4.5.4 Scan Area Options http://www.meier-geinitz.de/sane/sane2/0.07/doc014.html#s4.5.4 Shouldn't we add the usual standard-disclaimer: "This option is not mandatory, but if a backend does support it, it must implement it in a manner consistent with the above definition. "? |4.5.6 Gamma table options | The backend should not use the gamma tables to emulate other functions | or options like highlight, shadow, contrast, brightness, threshold, | analog_gamma. But doing a gamma table in software is allowed? I would move the Gamma table options to the Thershold, Annalog Gamma, Shadow and Highlight options, that's where it fits better than between depth and scan mode. | 4.5.9 Threshold http://www.meier-geinitz.de/sane/sane2/0.07/doc014.html#s4.5.9 | The option threshold is used to define the threshold for Lineart and | maybe Halftone mode. In multi bit modes this option should be set | inactive. The type of this option is SANE_TYPE_FIXED. The unit is | SANE_UNIT_PERCENT. The value range should be 0.0...100.0 if possible. | It defines the minimum intensity to get a white point / full intensity | (image data bit = 0). The bit is only 0 in RAW mode for gray frames. For color frames (the funny 1 bit color mode) it's one. And it may be anything for MIME types. So i would just remove "(image data bit = 0)", white point/full intensity is clear enough. Same for the rest of the text. I'll write about scan buttons in a separate email because that will become more complex, I guess. New Well Known Options: set focus position FOCUS_POS_X, FOCUS_POS_Y As I don't know what's the idea of that one, the proponent should explain :-) (From Oliver Rauch, the text is from me): "4.5.15 Batch scan options The batch scan options can be used by a frontend to indicate that more than one image will be scanned in a batch. The backend provides the options batch-scan-start, batch-scan-loop, batch-scan-end, batch-scan-next-tl-x, batch-scan-next-tl-y, batch-scan-next-br-x, and batch-scan-next-br-y. The first three options are of type SANE_TYPE_BOOL and indicate that the next scan is the first scan, the second or following or the last scan of a batch respectively. The batch-scan-next options specify the coordinates of the next scan and follow the same rules as the scan area option (see section ...). These options are not mandatory, but if a backend does support them, it must implement them in a manner consistent with the above definition. In this case, all options must be implemented." Some points of discussion: - Are all four geometry options necessary? If a device scans from top-to-bottom, tl-y would be sufficiant. However, there may exist device with a different scanning direction and the standard say, it's the job of the backend to transform coordinates. So we can't just redefine the top-left edge to something else. Do such devices exist? - Instead of three bool options, one sring-list option would be possible. This would avoid the case of more than one option is set by a misdirected frontend. On the other hand, these options should be handeld by the frontend, not the user so bool is easier to handle. Bye, Henning
