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Hex String to Doublebeware Hi all, I'm trying to decode some files. One of the values I need is stored as a double in hex. Example - "3fb999999999999a" -> "0.1". The double conversion here gets the correct result: https://gregstoll.dyndns.org/~gregstoll/floattohex/ currently my code just has the hex stored as a string (as in "set hexstr 3fb999999999999a"). How do I replicate the conversion done on that site?Martyn Smith The TCL command is binary, you need to convert the hexadecimal string to a binary string with binary format then extract the big endian double from the binary string as follows
binary scan [binary format H* $hexstr] Q floatValueThe Q is the format code for forced big endian double.
Google PhotosHas anyone written a tcl library that interfaces with [Google Photos] to allow one to download a "table of contents" of URLs to images and the albums to which they belong?
Image ScalingMiR 2018-06-28:On topic image scaling...I was wondering, if Tk would in the future implement at least a robust image scaling alogrithm like in TkImageTools from (reference see Shrinking an image)? It's just to avoid having to deploy an externel dynamic library just to have an image resized...AMG I did this just yesterday, but I'm probably not allowed to share the code though. I used libsamplerate  to do it. The interface works like this:[imgscale sourcePhoto targetPhoto ?method?]sourcePhoto and targetPhoto can be one-, three-, or five-element lists:
- operate on full extents of photo
- photoName width height
- explicit width and height, top left defaults to (0,0)
- photoName left top width height
- explicit width, height, and top left coordinates
- Use the Simple API  which consists of only the src_simple() function. The more complicated APIs offer no benefit in this application because the image data is all available in advance.
- Work on one channel (R, G, B, A) at a time. This requires less temporary space and offers better performance due to improved locality of reference and ability to use more optimized single-channel code within libsamplerate.
- Step 1: Loop over each row of input R, G, B, or A bytes.
- Step 1a: Convert the input row into a linear buffer of floats.
- Step 1b: Rescale the width and store into an intermediate float buffer large enough to hold the whole channel.
- Step 2: Transpose the intermediate buffer so that each column is contiguous in memory.
- Step 3: Loop over each column of intermediate floats.
- Step 3a: Rescale the height and store into a linear buffer of floats.
- Step 3b: Convert the scaled column back into pixel bytes, storing into a pixel buffer large enough for the whole image.
- Step 4: Use Tk_PhotoPutBlock() to write the pixel buffer to the target photo.
pitch = 1 pixelSize = height offset[n] = n * height * widthOne other tip. I statically linked libsamplerate into my extension. Another possibility is to incorporate a subset of the source code, removing the unused SINC modes, to avoid their large coefficient tables. (BSD 2-clause license, by the way.)