-
-
Notifications
You must be signed in to change notification settings - Fork 3k
/
qgsmapunitscale.h
83 lines (68 loc) · 2.79 KB
/
qgsmapunitscale.h
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
/***************************************************************************
qgsmapunitscale.h
Struct for storing maximum and minimum scales for measurements in map units
-------------------
begin : April 2014
copyright : (C) Sandro Mani
email : smani at sourcepole dot ch
***************************************************************************
* *
* 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. *
* *
***************************************************************************/
#ifndef QGSMAPUNITSCALE_H
#define QGSMAPUNITSCALE_H
#include <QtCore>
#include "qgsrendercontext.h"
/**
* \class QgsMapUnitScale
* \brief Struct for storing maximum and minimum scales for measurements in map units
*
* For measurements in map units, a minimum and a maximum scale can be defined.
* Outside this range, the measurements aren't scaled anymore proportionally to
* the map scale.
*/
class CORE_EXPORT QgsMapUnitScale
{
public:
/** Constructor for QgsMapUnitScale
* @param minScale minimum allowed scale, or 0.0 if no minimum scale set
* @param maxScale maximum allowed scale, or 0.0 if no maximum scale set
*/
QgsMapUnitScale( double minScale = 0.0, double maxScale = 0.0 ) : minScale( minScale ), maxScale( maxScale ) {}
/** The minimum scale, or 0.0 if unset */
double minScale;
/** The maximum scale, or 0.0 if unset */
double maxScale;
/** Computes a map units per pixel scaling factor, respecting the minimum and maximum scales
* set for the object.
* @param c render context
* @returns map units per pixel, limited between minimum and maximum scales
*/
double computeMapUnitsPerPixel( const QgsRenderContext& c ) const
{
double mup = c.mapToPixel().mapUnitsPerPixel();
double renderScale = c.rendererScale(); // Note: this value is 1 / scale
if ( minScale != 0 )
{
mup = qMin( mup / ( minScale * renderScale ), mup );
}
if ( maxScale != 0 )
{
mup = qMax( mup / ( maxScale * renderScale ), mup );
}
return mup;
}
bool operator==( const QgsMapUnitScale& other ) const
{
return minScale == other.minScale && maxScale == other.maxScale;
}
bool operator!=( const QgsMapUnitScale& other ) const
{
return minScale != other.minScale || maxScale != other.maxScale;
}
};
#endif // QGSMAPUNITSCALE_H