diff data/model/PowerOfSqrtTwoZoomConstraint.cpp @ 147:3a13b0d4934e

* Reorganising code base.  This revision will not compile.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/data/model/PowerOfSqrtTwoZoomConstraint.cpp	Mon Jul 31 11:44:37 2006 +0000
@@ -0,0 +1,104 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    This file copyright 2006 Chris Cannam.
+    
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#include "PowerOfSqrtTwoZoomConstraint.h"
+
+#include <iostream>
+#include <cmath>
+
+
+size_t
+PowerOfSqrtTwoZoomConstraint::getNearestBlockSize(size_t blockSize,
+						  RoundingDirection dir) const
+{
+    int type, power;
+    size_t rv = getNearestBlockSize(blockSize, type, power, dir);
+    return rv;
+}
+
+size_t
+PowerOfSqrtTwoZoomConstraint::getNearestBlockSize(size_t blockSize,
+						  int &type, 
+						  int &power,
+						  RoundingDirection dir) const
+{
+//    std::cerr << "given " << blockSize << std::endl;
+
+    size_t minCachePower = getMinCachePower();
+
+    if (blockSize < (1U << minCachePower)) {
+	type = -1;
+	power = 0;
+	float val = 1.0, prevVal = 1.0;
+	while (val + 0.01 < blockSize) {
+	    prevVal = val;
+	    val *= sqrt(2);
+	}
+	size_t rval;
+	if (dir == RoundUp) rval = size_t(val + 0.01);
+	else if (dir == RoundDown) rval = size_t(prevVal + 0.01);
+	else if (val - blockSize < blockSize - prevVal) rval = size_t(val + 0.01);
+	else rval = size_t(prevVal + 0.01);
+//	std::cerr << "returning " << rval << std::endl;
+	return rval;
+    }
+
+    unsigned int prevBase = (1 << minCachePower);
+    unsigned int prevPower = minCachePower;
+    unsigned int prevType = 0;
+
+    size_t result = 0;
+
+    for (unsigned int i = 0; ; ++i) {
+
+	power = minCachePower + i/2;
+	type = i % 2;
+
+	unsigned int base;
+	if (type == 0) {
+	    base = (1 << power);
+	} else {
+	    base = (((unsigned int)((1 << minCachePower) * sqrt(2) + 0.01))
+		    << (power - minCachePower));
+	}
+
+//	std::cerr << "Testing base " << base << std::endl;
+	if (base >= blockSize) {
+	    if (dir == RoundNearest) {
+		if (base - blockSize < blockSize - prevBase) {
+		    dir = RoundUp;
+		} else {
+		    dir = RoundDown;
+		}
+	    }
+	    if (dir == RoundUp) {
+		result = base;
+		break;
+	    } else {
+		type = prevType;
+		power = prevPower;
+		result = prevBase;
+		break;
+	    }
+	}
+
+	prevType = type;
+	prevPower = power;
+	prevBase = base;
+    }
+
+    if (result > getMaxZoomLevel()) result = getMaxZoomLevel();
+    return result;
+}