annotations.cpp File Reference

#include "annotations.h"
#include "annotations_p.h"
#include <QtGui/QApplication>
#include <QtGui/QColor>
#include <float.h>
#include "action.h"
#include "document.h"
#include "document_p.h"
#include "movie.h"
#include "page_p.h"
#include "sound.h"

Include dependency graph for annotations.cpp:

Go to the source code of this file.

Macros
#define	ADD_COORD(c1, c2)

Functions
static CaretAnnotation::CaretSymbol	caretSymbolFromString (const QString &symbol)
static QString	caretSymbolToString (CaretAnnotation::CaretSymbol symbol)
static double	distanceSqr (double x, double y, double xScale, double yScale, const QLinkedList< NormalizedPoint > &path)
static bool	isLeftOfVector (const NormalizedPoint &a, const NormalizedPoint &b, const NormalizedPoint &c)
static double	strokeDistance (double distance, double penWidth)

Macro Definition Documentation

#define ADD_COORD	(		c1,
			c2
	)

Value:

{ \
  c1.x = c1.x + c2.x; \
  c1.y = c1.y + c2.y; \
}

Function Documentation

static CaretAnnotation::CaretSymbol caretSymbolFromString ( const QString &  symbol )

static

Definition at line 2378 of file annotations.cpp.

static QString caretSymbolToString ( CaretAnnotation::CaretSymbol  symbol )

static

Definition at line 2366 of file annotations.cpp.

static double distanceSqr ( double  x, double  y, double  xScale, double  yScale, const QLinkedList< NormalizedPoint > &  path  )

static

Calculates distance of the given point x y xScale yScale to the path.

Does piecewise comparison and selects the distance to the closest segment

Definition at line 45 of file annotations.cpp.

static bool isLeftOfVector ( const NormalizedPoint &  a, const NormalizedPoint &  b, const NormalizedPoint &  c  )

static

True, if point c lies to the left of the vector from a to b.

Definition at line 34 of file annotations.cpp.

static double strokeDistance ( double  distance, double  penWidth  )

static

Given the squared distance from the idealized 0-width line and a pen width penWidth, (not squared!), returns the final distance.

Warning

The returned distance is not exact: We calculate an (exact) squared distance to the ideal (centered) line, and then subtract the squared width of the pen: a^2 - b^2 where a = "distance from idealized 0-width line" b = "pen width" For an exact result, we would want to calculate "(a - b)^2" but that would require a square root operation because we only know the squared distance a^2.

However, the approximation is feasible, because: error = (a-b)^2 - (a^2 - b^2) = -2ab + 2b^2 = 2b(b - a) Therefore: lim_{a->b} a^2 - b^2 - a^2 + 2ab - b^2 –> 0

In other words, this approximation will estimate the distance to be slightly more than it actually is for as long as we are far "outside" the line, becoming more accurate the closer we get to the line boundary. Trivially, it also fulfils (a1 < a2) => ((a1^2 - b^2) < (a2^2 - b^2)) making it monotonic. "Inside" of the drawn line, the distance is 0 anyway.

Definition at line 84 of file annotations.cpp.