[Plib-users] Bugreport: fntTexFont::getBBox produces wrong size if spaces are present in string

[Jan Schaefer(local) <ta...@gm...>]

(I sent this message twice, because it didn't appear in the archives 
after the first time, propably because I used an email-address which 
isn't subsribed to plib-users. I hope it doesn't appear twice.)


Hello PLIB-developers,

I'm experiencing some strange behaviour from fntTexFont::getBBox.
Actually I'm using PUI to draw a GUI and try to layout the width of a
frame according to the width of a string. I put the string into
puFont::getStringWidth to determine the width. If the string doesn't
contain any newlines, everything works fine. But if any number of
newlines is present, and any of the lines but the first contain spaces,
the width is calculated to large. The effect seems to be somehow
proportional to the number of spaces present.
I wrote a small example program to eliminate as many other influences as
possible, you can find it below. It would be really nice if you could
have a look at it, maybe I'm just doing something wrong. The
Helvetica.txf file used for the fntTexFont is taken from the
plib_examples-1.8.4.tar.gz.
The program outputs the results of getBBox twice. The right value
differs, even though the string contains exactly the same lines, just in
a different order.
I already had a look at fntTexFont::getBBox, but couldn't find a mistake.

#include <stdlib.h>
#include <stdio.h>
#include <string>
#include <iostream>
#include <GL/glut.h>
#include <plib/pu.h>
#include <plib/fnt.h>

int window;
puFrame* frame = 0;
puText* text = 0;
fntTexFont* texFnt = 0;
puFont* font = 0;
std::string str = "";

void displayFunc(void) {
    glClear(GL_COLOR_BUFFER_BIT);

    puDisplay();

    glutSwapBuffers();

}

int main(int argc, char** argv) {

    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(640, 480);
    glutInitWindowPosition(0, 0);
    window = glutCreateWindow(argv[0]);

    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glClearColor (0.0, 0.0, 0.0, 0.0);
    glEnable(GL_BLEND);

    glutIdleFunc(displayFunc);
    glutDisplayFunc(displayFunc);

    puInit();

    str = "123456789012345678901234567890\n1 3 5 7 9 1 3 5 7 9 1 3 5 7 9
\n123456789012345678901234567890";
    frame = new puFrame(0,0,0,0);
    text = new puText(0,0);
    texFnt = new fntTexFont();
    if(!texFnt->load(std::string("Helvetica.txf").c_str())) {
        std::cout <<     "Error loading font file Helvetica.txf" <<
std::endl;
        exit(0);
    }
    float l = 0;
    float r = 0;
    float t = 0;
    float b = 0;
    texFnt->getBBox(str.c_str(), 18, 0.0f, &l, &r, &b, &t);
    std::cout << "1. BBox: " << l << ", " << b << ", " << r << ", " << t
<< std::endl;
    str = "1 3 5 7 9 1 3 5 7 9 1 3 5 7 9
\n123456789012345678901234567890\n123456789012345678901234567890";
    texFnt->getBBox(str.c_str(), 18, 0.0f, &l, &r, &b, &t);
    std::cout << "2. BBox: " << l << ", " << b << ", " << r << ", " << t
<< std::endl;

    font = new puFont(texFnt, 18, 0.0f);
    text->setLabelFont(*font);
    text->setLabel(str.c_str());
    text->setColor(PUCOL_LABEL, 0.0f, 0.0f, 0.0f, 1.0f);
    text->setPosition(0, font->getStringHeight(str.c_str()) +
font->getStringDescender() - font->getStringHeight());
    frame->setSize(font->getStringWidth(str.c_str()),
font->getStringHeight(str.c_str()) + font->getStringDescender());
    frame->setStyle(PUSTYLE_BOXED);
    frame->setColor(PUCOL_FOREGROUND, 1.0f, 1.0f, 1.0f, 1.0f);
    frame->setColor(PUCOL_HIGHLIGHT, 1.0f, 1.0f, 1.0f, 1.0f);
    frame->setColor(PUCOL_BACKGROUND, 0.8f, 0.8f, 0.8f, 1.0f);

    // run GLUT
    glutMainLoop();

    puDeleteObject(text);
    puDeleteObject(frame);
    delete font;
    delete texFnt;

    glutDestroyWindow(window);

    return 1;
}