Rotated text using Drawtext

[Mary Chennai]

Hi, I have used the code below to draw rotated text using DrawText. //Draw rotated text double Escapement = -401; CString str = "Hello World"; CFont newFont; newFont.CreateFont(24, 0, Escapement, Escapement, 0, 0, 0, 0, 0, 0, 0, 0, 0, "Arial"); CFont* pFont = pDC->SelectObject(&newFont); // draw the text CSize TextSize = pDC->GetTextExtent(str); CRect rect(0,0,TextSize.cx, TextSize.cy); pDC->DrawText(str, str.GetLength(), rect, DT_CENTER); Text is diplayed fine for non-rotated text. But for rotated text(ie, with Escapemnt != 0), the text appears to be clipped or sometimes not displayed at all. This is because the rect value is too restrictive for rotated text. Please can someone help me to deduce the rect value correctly for rotated texts? Regards Mary

[Chris Losinger]

you might try using DrawText with the DT_CALCRECT flag

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[Mary Chennai]

Yes I tried using DT_CALCRECT. But that isn't giving me a rotated rectangle.

[Luc Pattyn]

FYI: 1. DT_CALCRECT returns the size of the bounding rectangle. 2. A rotated rectangle is still a rectangle. :)

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Please use <PRE> tags for code snippets, they preserve indentation, and improve readability.

[Maximilien]

Me think the rectangle is aligned to the coordinate system or the "screen", not to the coordinate system of the rotated text.

Watched code never compiles.

[CPallini]

As suggested by Maximilien the computed rectangle is always aligned to screen coordinate space (i.e. rotation is not performed). The following code (warning is a quick and dirty hack...)

#include <float.h>
#include <math.h>

//..

// draw the text
CSize TextSize = dc.GetTextExtent(str);
//CRect rect(0,0,TextSize.cx, TextSize.cy);

double x[4],y[4];
double alpha = ((double) Escapement) * atan(1.) * 4 / 1800;
x[0] = .0;
y[0] = .0;
x[1] = TextSize.cx * cos(alpha);
y[1] = -TextSize.cx * sin(alpha);
x[2] = TextSize.cx * cos(alpha) +TextSize.cy * sin(alpha);
y[2] = - TextSize.cx * sin(alpha) + TextSize.cy * cos(alpha);
x[3] = TextSize.cy * sin(alpha);
y[3] = TextSize.cy *cos(alpha);

double xoff=0.,yoff = 0.;
for (int i=0; i<4; i++)
{
if ( xoff > x[i] ) xoff = x[i];
if ( yoff > y[i] ) yoff = y[i];
}
for (int i=0; i<4; i++)
{
x[i]-=xoff;
y[i]-=yoff;
}
dc.MoveTo(x[0],y[0]);
dc.LineTo(x[1],y[1]);
dc.LineTo(x[2],y[2]);
dc.LineTo(x[3],y[3]);
dc.LineTo(x[0],y[0]);

double xmin = DBL_MAX;
double ymin = DBL_MAX;
double xmax = 0.;
double ymax = 0.;
for (int i=0; i<4; i++)
{
if (xmin > x[i]) xmin = x[i];
if (ymin > y[i]) ymin = y[i];
if (xmax < x[i]) xmax = x[i];
if (ymax < y[i]) ymax = y[i];
}
CBrush *pOldBrush = (CBrush*)dc.SelectStockObject(NULL_BRUSH);
dc.Rectangle(xmin, ymin, xmax, ymax);
dc.SelectObject(pOldBrush);

CRect rect(xmin-xoff,ymin,xmax-xoff,ymax);

dc.DrawText(str, str.GetLength(), rect, DT_NOCLIP);
//...

Shows you:

• The 'rotated text bounding rectangle'
• The 'screen aligned rectangle' bounding the rotated one
• The rotated text

:)

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