std::vector<TextFlow::Word> TextFlow::calculateWord(std::u16string content, int maxPixelWidth, float scale) const
{
// Calculate word from content
Word word = calculateWord(content, scale);
// End of recursion
if ((content.size() == 1 && word.pixelWidth > maxPixelWidth) || content.empty())
{
// Return empty vector as signal of failure
return std::vector<Word>();
}
else if (word.pixelWidth <= maxPixelWidth)
{
// If word length is ok, just return it
return std::vector<Word>(1, word);
}
else
{
// Word is too wide and content longer than 1, split it!
int length = (int)content.size();
int left = length / 2;
int right = length - left;
// Combine results from recursive call
std::vector<Word> leftWord = calculateWord(content.substr(0, left), maxPixelWidth, scale);
std::vector<Word> rightWord = calculateWord(content.substr(left+1, right), maxPixelWidth, scale);
// If one or more of both are empty, forget it
if (leftWord.empty() || rightWord.empty())
{
return std::vector<Word>();
}
else
{
std::vector<Word> words(leftWord);
words.insert(words.end(), rightWord.begin(), rightWord.end());
return words;
}
}
}
bool TextFlow::insertWord(std::vector<TextFlow::Word>& rWords, const std::u16string& rContent, int maxPixelWidth, float scale) const
{
// Do nothing if input is empty
if (rContent.empty())
{
return true;
}
std::vector<Word> newWords = calculateWord(rContent, maxPixelWidth, scale);
// Check, whether call was successful
if (newWords.empty())
{
// Was not successful, so return false
return false;
}
else
{
// Insert new words and return true
rWords.insert(rWords.end(), newWords.begin(), newWords.end());
return true;
}
}
void TextFlow::specialCalculateMesh(
std::u16string streamlinedContent,
float lineHeight, std::vector<glm::vec3>& rVertices,
std::vector<glm::vec2>& rTextureCoordinates)
{
// Reset flow width to get longest line's width of this computation
mFlowWidth = 0;
// OpenGL setup done in calling method
// Get size of space character
float pixelOfSpace = 0;
Glyph const * pGlyph = mpFont->getGlyph(mFontSize, u' ');
if (pGlyph == NULL)
{
throwWarning(
OperationNotifier::Operation::RUNTIME,
"TextFlow creation does not find space sign in font");
}
else
{
pixelOfSpace = mScale * pGlyph->advance.x;
}
// Create mark for overflow
Word overflowMark = calculateWord(TEXT_FLOW_OVERFLOW_MARK, mScale);
// Get pararaphs separated by \n
std::vector<std::u16string> paragraphs;
std::u16string paragraphDelimiter = u"\n";
// Seperate into paragraphs
size_t pos = 0;
std::u16string token;
while ((pos = streamlinedContent.find(paragraphDelimiter)) != std::u16string::npos)
{
token = streamlinedContent.substr(0, pos);
paragraphs.push_back(token);
streamlinedContent.erase(0, pos + paragraphDelimiter.length());
}
paragraphs.push_back(streamlinedContent); // Last paragraph (paragraphs never empty)
// Do not generate text flow mesh when there is a failure
bool failure = false;
// Go over paragraphs (pens are in local pixel coordinate system with origin in lower left corner of element)
float yPixelPen = -lineHeight; // First line should be also inside flow
for (std::u16string& rPargraph : paragraphs)
{
// Get words out of paragraph
std::vector<Word> words;
std::u16string wordDelimiter = u" ";
while ((pos = rPargraph.find(wordDelimiter)) != std::u16string::npos)
{
token = rPargraph.substr(0, pos);
rPargraph.erase(0, pos + wordDelimiter.length());
failure |= !insertFitWord(words, token, mWidth, mScale);
}
// Add last token from paragraph as well
failure |= !insertFitWord(words, rPargraph, mWidth, mScale);
// Failure appeared, forget it
if (!failure)
{
// Prepare some values
uint wordIndex = 0;
bool hasNext = !words.empty();
// Go over lines to write paragraph
while (hasNext && abs(yPixelPen) <= mHeight)
{
// Collect words in one line
std::vector<Word const *> line;
float wordsPixelWidth = 0;
float newWordsWithSpacesPixelWidth = 0;
// Still words in the paragraph and enough space? Fill into line!
while (hasNext && newWordsWithSpacesPixelWidth <= mWidth)
{
// First word should always fit into width because of previous checks
wordsPixelWidth += words[wordIndex].pixelWidth;
line.push_back(&words[wordIndex]);
wordIndex++;
if (wordIndex >= words.size())
{
// No words in paragraph left
hasNext = false;
}
else
{
// Calculate next width of line
newWordsWithSpacesPixelWidth = std::ceil(
(wordsPixelWidth + (float)words[wordIndex].pixelWidth) // Words size (old ones and new one)
+ (((float)line.size()) - 1.0f) * pixelOfSpace); // Spaces between words
}
}
// If this is last line and after it still words left, replace it by some mark for overflow
if (hasNext && abs(yPixelPen - lineHeight) > mHeight && overflowMark.pixelWidth <= mWidth)
{
line.clear();
wordsPixelWidth = overflowMark.pixelWidth;
line.push_back(&overflowMark);
}
// Remember longest line's width
mFlowWidth = mFlowWidth < ((int) wordsPixelWidth + 1) ? ((int)wordsPixelWidth + 1) : mFlowWidth;
// Decide dynamic space for line
float dynamicSpace = pixelOfSpace;
if (line.size() > 1)
{
if (mAlignment == TextFlowAlignment::JUSTIFY && hasNext && line.size() > 1) // Do not use dynamic space for last line
{
// For justify, do something dynamic
dynamicSpace = ((float)mWidth - wordsPixelWidth) / ((float)line.size() - 1.0f);
}
else
{
// Adjust space to compensate precision errors in other alignments
float calculatedDynamicSpace = (float)mWidth - (wordsPixelWidth / (float)(line.size() - 1));
dynamicSpace = std::min(dynamicSpace, calculatedDynamicSpace);
}
}
// Now decide xOffset for line
float xOffset = 0;
if (mAlignment == TextFlowAlignment::RIGHT || mAlignment == TextFlowAlignment::CENTER)
{
xOffset = (float)mWidth - ((wordsPixelWidth + ((float)line.size() - 1.0f) * dynamicSpace));
if (mAlignment == TextFlowAlignment::CENTER)
{
xOffset = xOffset / 2.0f;
}
}
// Combine word geometry to one line
float xPixelPen = xOffset;
for (uint i = 0; i < line.size(); i++)
{
// Assuming, that the count of vertices and texture coordinates is equal
for (uint j = 0; j < line[i]->spVertices->size(); j++)
{
const glm::vec3& rVertex = line[i]->spVertices->at(j);
rVertices.push_back(glm::vec3(rVertex.x + xPixelPen, rVertex.y + yPixelPen, rVertex.z));
const glm::vec2& rTextureCoordinate = line[i]->spTextureCoordinates->at(j);
rTextureCoordinates.push_back(glm::vec2(rTextureCoordinate.s, rTextureCoordinate.t));
}
// Advance xPen
xPixelPen += dynamicSpace + line[i]->pixelWidth;
}
// Advance yPen
yPixelPen -= lineHeight;
}
}
}
// If failure appeared, clean up
if (failure)
{
// Vertex count will become zero
rVertices.clear();
rTextureCoordinates.clear();
}
// Get height of all lines (yPixelPen is one line to low now)
mFlowHeight = (int)std::max(std::ceil(abs(yPixelPen) - lineHeight), 0.0f);
}
