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# Wrapping My Head Around Word Wrapping Code...

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I'm trying to get my FontString class to print word-wrapped text within a certain height, but I'm not sure the best way of going about this. Here's my latest attempt (I have another version that does this character-by-character):

int startIndex = 0;
int startSpriteIndex = 0;
int numWordsOnLine = 0;
Vector2 offset;
Sprite *sprite = NULL;

int specialCharIndex = 0;
int startLineIndex = 0;
float spacing = 0.0f;
float glyphWidth = 0.0f;
bool stopUpdating = false;

// remove sprites
batch->RemoveAllSprites();
sprites.clear();
if(!fontPtr) return;
numLines = 1;

// print the text word-by-word
for(int i=0;i<numWords;i++)
{
int specialCharacter = 0;
int index = startIndex;
float wordWidth = 0.0f;

// stop updating the text if deprecated
if(stopUpdating) break;

// get the number of characters in the word
while(index < (int)text.size())
{
// stop counting if a special character was found
if(text[index] == ' ' || text[index] == '\t' || text[index] == '\n' || text[index] == '\0')
{
specialCharacter = (int)text[index];
break;
}
index++; // increment the index
}

// get the word's length
for(int e=startIndex;e<index;e++)
{
FontGlyph *glyph = fontPtr->GetGlyph(text[e], false);
if(!glyph) continue;
}

// wrap the word down to the next line
if(offset.x + wordWidth >= dimensions.x && dimensions.x > 0.0f)
{
// process alignment
if(horizontalAlign != FONT_ALIGN_LEFT)
{
// modify the xExtent based on alignment
float xExtent = dimensions.x - offset.x;
if(horizontalAlign == FONT_ALIGN_CENTER)
xExtent *= 0.5f;
//printf("xExtent: %f - %f = %f\n", dimensions.x, offset.x, xExtent);

// space the sprites accordingly
for(int e=startSpriteIndex;e<(int)sprites.size();e++)
{
sprite = (Sprite*)sprites[e];
sprite->Translate(Vector3(xExtent, 0.0f, 0.0f));
}
startSpriteIndex = (int)sprites.size();
}

// go to the next line
if(deprecated) stopUpdating = true;
offset.x = 0.0f;
offset.y += (float)fontPtr->GetCommonData().lineHeight;
numWordsOnLine = 0;
numLines++;
} else numWordsOnLine++;

// set the sprites
for(int e=startIndex;e<index;e++)
{
FontGlyph *glyph = fontPtr->GetGlyph(text[e], false);
if(!glyph) continue;

// add the sprite to the list and set its parameters
sprite = new Sprite("");
TexCoords glyphDims((short)glyph->width, (short)glyph->height);
TexCoords glyphPos((short)glyph->x, (short)glyph->y);
sprite->Blit(glyphDims, glyphPos);
sprite->SetColor(color);

// translate and push the sprite into the batch
Vector3 spritePosition(position.x + (float)glyph->xOffset + ((float)sprite->GetDimensions().x / 2.0f) + offset.x, position.y + (float)glyph->yOffset + ((float)sprite->GetDimensions().y / 2.0f) + offset.y, 0.0f);
sprite->Translate(spritePosition);
sprites.push_back(sprite);
offset.x += (float)glyph->width;
}

// add spacing to the offset based on the special character
switch(specialCharacter)
{
case (int)' ':
offset.x += fontPtr->fixed.x;
break;

case (int)'\t':
offset.x += fontPtr->fixed.x * fontPtr->numTabSpaces;
break;

case (int)'\n':
// process alignment
if(horizontalAlign != FONT_ALIGN_LEFT)
{
// modify the xExtent based on alignment
float xExtent = dimensions.x - offset.x;
if(horizontalAlign == FONT_ALIGN_CENTER)
xExtent *= 0.5f;
//printf("xExtent: %f - %f = %f\n", dimensions.x, offset.x, xExtent);

// space the sprites accordingly
for(int e=startSpriteIndex;e<(int)sprites.size();e++)
{
sprite = (Sprite*)sprites[e];
sprite->Translate(Vector3(xExtent, 0.0f, 0.0f));
}
startSpriteIndex = (int)sprites.size();
}

startSpriteIndex = (int)sprites.size();
if(deprecated) stopUpdating = true;
offset.x = 0.0f;
offset.y += fontPtr->GetCommonData().lineHeight;
numWordsOnLine = 0;
numLines++;
break;
}
startIndex = index+1;
}


I'm pretty lost at this point... This algorithm nearly works, except if there's only 1 word in the line, then that word becomes right-aligned. Same happens when a newline character is found, and there's some issues with tabbing.

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I rewrote my code for a 3rd or 4th time, but eventually, I think I've got it! For those of you looking at how to implement word-wrap in C-like languages, here's my C++ implementation on how I did it:

void FontString::UpdateText()
{
if(!fontPtr) return;

bool nextLine = false;
bool endLineFound = false;
float lineWidth = 0.0f;
int startIndex = 0;
int endIndex = 0;
Vector2 offset;

// handle zero width
if(!GetDimensions().x)
{
// process each character
for(int i=0;i<(int)text.size();i++)
{
// handle spacing characters
switch(text[i])
{
case ' ':
case '\t':
offset.x += GetGlyphWidth(i);
continue;

case '\n':
case '\r':
return;
}

offset.x += GetGlyphWidth(i);
}

// set dimensions and vertex buffer
dimensions.x = offset.x;
dimensions.y = fontPtr->GetCommonData().lineHeight;
if(vertexBuffer)
{
vertexBuffer->GetVertex(0)->position = Vector2(position.x, position.y);
vertexBuffer->GetVertex(1)->position = Vector2(position.x, position.y) + Vector2(dimensions.x, 0.0f);
vertexBuffer->GetVertex(2)->position = Vector2(position.x, position.y) + dimensions;
vertexBuffer->GetVertex(3)->position = Vector2(position.x, position.y) + Vector2(0.0f, dimensions.y);
}
return;
}

// handle text areas with fixed width
for(int i=0;i<(int)text.size();i++)
{
// handle spacing characters
switch(text[i])
{
case '\r':
case '\n':
endIndex = i;
nextLine = true;
break;

case '\0':
break;

default:
lineWidth += GetGlyphWidth(i);
break;
}

// check if the end of the line is reached
if(lineWidth >= GetDimensions().x || i == (text.size()-1))
{
// check if at the end of the line
if(i == text.size()-1)
endIndex = (int)text.size()-1;
else {
// find end index
switch(i)
{
case ' ':
case '\t':
case '\n':
case '\r':
endIndex = i;
break;

// roll back to the beginning of the word
default:
// look backwards for a spacing character from current spot
for(int e=i;e>=0;e--)
{
// check for spacing characters
switch(text[e])
{
case ' ':
case '\t':
case '\n':
case '\r':
endIndex = e;
endLineFound = true;
break;
}

// stop searching if end of line character found
lineWidth -= GetGlyphWidth(e);
if(endLineFound) break;
}
break;
}
}
nextLine = true;
}

// check if spacing has gone beyond line width
if(nextLine)
{
// set offset based on alignment
switch((int)horizontalAlign)
{
case FONT_ALIGN_LEFT:
offset.x = 0.0f;
break;

case FONT_ALIGN_CENTER:
offset.x = (GetDimensions().x - lineWidth) / 2.0f;
break;

case FONT_ALIGN_RIGHT:
offset.x = GetDimensions().x - lineWidth;
break;

default:
offset.x = 0.0f;
break;
}

for(int e=startIndex;e<endIndex;e++)
{
offset.x += GetGlyphWidth(e);
}

// reset variables
lineWidth = 0.0f;
offset.y += fontPtr->GetCommonData().lineHeight;
startIndex = endIndex + 1; // skip newline character
i = startIndex - 1; // set i to startIndex but subtract 1 due to incrementation
endLineFound = false;
nextLine = false;
if(deprecated) break; // stop processing the loop after the line
}
}

// calculate the height
if(sprites.size())
{
if(!batch) return;
SpriteVertices *topVertices = batch->GetVertexListElement(0);
SpriteVertices *bottomVertices = batch->GetVertexListElement((int)sprites.size()-1);

// find the difference
if(!topVertices || !bottomVertices) return;
dimensions.y = bottomVertices->vertex[5].position.y - topVertices->vertex[0].position.y;
} else
dimensions.y = 0.0f;
}


I hope the comments are clear enough on how this works. What I do is loop through each character in an std::string (I'm assuming it's 1 character per element, and not that weird two elements can equal a 16-bit UNICODE-ish character). I assume that you've already loaded a bitmapped font, and GetGlyphWidth(int index) will return the width of that character in pixels. Keep in mind that GetGlyphWidth's "index" parameter refers to the current element index in the string, and not the value of that element.

With each character iteration, I add that character's width to the current line's length called lineWidth. Once it's equal or exceeded the margin, I know it's time to find the starting and ending indexes in my string for that line, add and blit sprites between those indices, etc. The issue is, a line break will be found in the middle of the string, most of the time. So, what I do is see if the line break occurred in a whitespace such as newline, tab, space, etc, which means that I'm not in the middle of a word, and I can just set to ending index for that line at line breaking character. If not, I'm in the middle of a word, and I need to use a second loop to roll backward into the string to find the previous whitespace.

Once startIndex and endIndex are set, I flag that a new line was found with nextLine, and I proceed to setup the sprites, and reset variables for the next line. After the text is complete, I compute a bounding box for frustum checks, and create a vertex buffer for drawing the box if needed (vertex buffer setup isn't in the code).

I really hope this helps some one out!

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