mirror of https://github.com/xzeldon/htop.git
Change variable 'dot' to avoid division by reciprocal.
(Cherry-picked from d56bcd8e0d8d6a177fc2e40db32fc73ea4588684, the experimental graph coloring branch) The variable 'dot' in GraphMeterMode_draw now means "maximum number of dots per value (column) in graph". The old meaning was "amount of value that is to be represented by a dot" and was always a fraction. Due to a limitation in floating point computing, if GRAPH_HEIGHT were not a power of 2, then rounding errors will occur on numbers like (1.0/3). (Currently GRAPH_HEIGHT is 4 and so no precision loss.) 'dot' was used as a divisor, and it's "division by a reciprocal". We change that to simple multiplication.
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Meter.c
6
Meter.c
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@ -408,9 +408,9 @@ static void GraphMeterMode_draw(Meter* this, int x, int y, int w) {
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}
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for (int i = nValues - (w*2) + 2, k = 0; i < nValues; i+=2, k++) {
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const double dot = (1.0 / (GraphMeterMode_pixPerRow * GRAPH_HEIGHT));
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int v1 = CLAMP(data->values[i] / dot, 1, GraphMeterMode_pixPerRow * GRAPH_HEIGHT);
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int v2 = CLAMP(data->values[i+1] / dot, 1, GraphMeterMode_pixPerRow * GRAPH_HEIGHT);
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int pix = GraphMeterMode_pixPerRow * GRAPH_HEIGHT;
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int v1 = CLAMP(data->values[i] * pix, 1, pix);
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int v2 = CLAMP(data->values[i+1] * pix, 1, pix);
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int colorIdx = GRAPH_1;
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for (int line = 0; line < GRAPH_HEIGHT; line++) {
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