Crafter.Graphics/implementations/Crafter.Graphics-TextElement.cpp

/*
Crafter®.Graphics
Copyright (C) 2025 Catcrafts®
Catcrafts.net

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3.0 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
*/

module;
#include "../lib/stb_truetype.h"
module Crafter.Graphics:TextElement_impl;
import :TextElement;
import :RenderingElement;
import :Window;
import :Types;
import :Font;
import std;

using namespace Crafter;

TextElement::TextElement(std::int_fast32_t anchorX, std::int_fast32_t anchorY, std::uint_fast32_t relativeWidth, std::uint_fast32_t relativeHeight, std::int_fast32_t anchorOffsetX, std::int_fast32_t anchorOffsetY, std::int_fast32_t z, bool ignoreScaling) : RenderingElementPreScaled(false, anchorX, anchorY, relativeWidth, relativeHeight, anchorOffsetX, anchorOffsetY, z, ignoreScaling) {

}

void TextElement::RenderText(const std::string_view text, float size, Pixel_BU8_GU8_RU8_AU8 color, Font& font, TextAlignment alignment, TextOverflowMode overflowMode) {
    // Calculate the actual size needed for the text
    float scale = stbtt_ScaleForPixelHeight(&font.font, size);
    int baseline = (int)(font.ascent * scale);

    // Clear the scaled buffer
    for (auto& pixel : bufferScaled) {
        pixel = {0, 0, 0, 0};
    }

    // If we have no text or no space, return early
    if (text.empty() || scaled.width == 0 || scaled.height == 0) {
        return;
    }

    // Handle text overflow based on mode
    if (overflowMode == TextOverflowMode::Clip) {
        // We need to handle line breaks and calculate lines
        std::vector<std::string_view> lines;
        std::string_view remaining = text;
        
        while (!remaining.empty()) {
            // Find next newline or end of string
            auto newlinePos = remaining.find('\n');
            if (newlinePos != std::string_view::npos) {
                lines.emplace_back(remaining.substr(0, newlinePos));
                remaining = remaining.substr(newlinePos + 1);
            } else {
                lines.emplace_back(remaining);
                break;
            }
        }

        // Now process each line
        std::uint_fast32_t lineHeight = (font.ascent - font.descent) * scale;
        std::uint_fast32_t maxLineWidth = scaled.width;
        std::uint_fast32_t currentLineStartY = 0;
        
        for (std::size_t lineIndex = 0; lineIndex < lines.size(); ++lineIndex) {
            std::string_view line = lines[lineIndex];
            
            // Calculate line width
            std::uint_fast32_t lineWidth = 0;
            std::vector<int> lineAdvances;
            for (const char c : line) {
                int advance, lsb;
                stbtt_GetCodepointHMetrics(&font.font, c, &advance, &lsb);
                lineAdvances.push_back(advance);
                lineWidth += (int)(advance * scale);
            }
            
            // Determine horizontal position based on alignment
            int startX = 0;
            switch (alignment) {
                case TextAlignment::Left:
                    startX = 0;
                    break;
                case TextAlignment::Center:
                    startX = (scaled.width - lineWidth) / 2;
                    break;
                case TextAlignment::Right:
                    startX = scaled.width - lineWidth;
                    break;
            }
            
            // Render the line
            int x = startX;
            int startY = currentLineStartY + baseline + (lineIndex * lineHeight);
            
            for (std::size_t i = 0; i < line.size(); ++i) {
                int codepoint = line[i];
                
                int ax;
                int lsb;
                stbtt_GetCodepointHMetrics(&font.font, codepoint, &ax, &lsb);

                int c_x1, c_y1, c_x2, c_y2;
                stbtt_GetCodepointBitmapBox(&font.font, codepoint, scale, scale, &c_x1, &c_y1, &c_x2, &c_y2);

                int w = c_x2 - c_x1;
                int h = c_y2 - c_y1;

                std::vector<unsigned char> bitmap(w * h);
                stbtt_MakeCodepointBitmap(&font.font, bitmap.data(), w, h, w, scale, scale, codepoint);

                // Only render characters that fit within the scaled bounds
                for (int j = 0; j < h; j++) {
                    for (int i = 0; i < w; i++) {
                        int bufferX = x + i + c_x1;
                        int bufferY = startY + j + c_y1;
                        
                        // Only draw pixels that are within our scaled buffer bounds
                        if (bufferX >= 0 && bufferX < (int)scaled.width && bufferY >= 0 && bufferY < (int)scaled.height) {
                            bufferScaled[bufferY * scaled.width + bufferX] = {color.r, color.g, color.b, bitmap[j * w + i]};
                        }
                    }
                }

                x += (int)(ax * scale);

                if (i + 1 < line.size()) {
                    x += (int)stbtt_GetCodepointKernAdvance(&font.font, codepoint, line[i+1]);
                }
            }
            
            currentLineStartY += lineHeight;
        }
    } else if (overflowMode == TextOverflowMode::Wrap) {
        // Implement word wrapping
        std::uint_fast32_t lineHeight = (font.ascent - font.descent) * scale;
        std::uint_fast32_t maxLineWidth = scaled.width;
        std::uint_fast32_t currentLineStartY = 0;
        
        // Process text character by character to wrap words
        std::string remaining(text);
        std::string currentLine;
        std::string lastWord;
        std::string currentWord;
        
        while (!remaining.empty()) {
            // Find next word boundary
            std::size_t nextSpace = remaining.find(' ');
            std::size_t nextNewline = remaining.find('\n');
            
            // Find the earliest delimiter
            std::size_t delimiterPos = std::string_view::npos;
            if (nextSpace != std::string_view::npos) {
                delimiterPos = nextSpace;
            }
            if (nextNewline != std::string_view::npos && (delimiterPos == std::string_view::npos || nextNewline < delimiterPos)) {
                delimiterPos = nextNewline;
            }
            
            // Extract word
            if (delimiterPos != std::string_view::npos) {
                currentWord = remaining.substr(0, delimiterPos);
                remaining = remaining.substr(delimiterPos + 1);
            } else {
                currentWord = remaining;
                remaining = {};
            }
            
            // Check if adding this word would exceed the line width
            std::uint_fast32_t wordWidth = 0;
            for (const char c : currentWord) {
                int advance, lsb;
                stbtt_GetCodepointHMetrics(&font.font, c, &advance, &lsb);
                wordWidth += (int)(advance * scale);
            }
            
            // Add kerning for spaces between words
            if (!currentLine.empty() && !currentWord.empty()) {
                int lastChar = currentLine.back();
                int firstChar = currentWord.front();
                wordWidth += (int)stbtt_GetCodepointKernAdvance(&font.font, lastChar, firstChar);
            }
            
            // If this word alone is wider than the line, force break it
            if (wordWidth > maxLineWidth) {
                // Force break the word
                if (!currentLine.empty()) {
                    // Render current line
                    RenderWrappedLine(currentLine, scale, baseline, currentLineStartY, color, font, alignment);
                    currentLineStartY += lineHeight;
                    currentLine = {};
                }
                
                // Break the long word into parts
                std::string_view wordPart = currentWord;
                while (!wordPart.empty()) {
                    // Find a good place to break the word
                    std::size_t breakPos = 0;
                    std::uint_fast32_t currentWidth = 0;
                    
                    for (std::size_t i = 0; i < wordPart.length(); ++i) {
                        int advance, lsb;
                        stbtt_GetCodepointHMetrics(&font.font, wordPart[i], &advance, &lsb);
                        currentWidth += (int)(advance * scale);
                        
                        if (currentWidth > maxLineWidth) {
                            breakPos = i;
                            break;
                        }
                    }
                    
                    if (breakPos == 0) {
                        breakPos = wordPart.length();
                    }
                    
                    std::string_view part = wordPart.substr(0, breakPos);
                    // Render the part
                    RenderWrappedLine(part, scale, baseline, currentLineStartY, color, font, alignment);
                    currentLineStartY += lineHeight;
                    wordPart = wordPart.substr(breakPos);
                }
            } else if (currentLine.empty() || (currentLine.length() + currentWord.length() + 1) * (int)(scale * 1.5f) <= maxLineWidth) {
                // Add word to current line
                if (!currentLine.empty()) {
                    currentLine = currentLine.substr(0) + std::string(" ") + currentWord;
                } else {
                    currentLine = currentWord;
                }
            } else {
                // Render current line and start new one
                RenderWrappedLine(currentLine, scale, baseline, currentLineStartY, color, font, alignment);
                currentLineStartY += lineHeight;
                currentLine = currentWord;
            }
        }
        
        // Render final line if it exists
        if (!currentLine.empty()) {
            RenderWrappedLine(currentLine, scale, baseline, currentLineStartY, color, font, alignment);
        }
    }
}

// Helper method to render a wrapped line
void TextElement::RenderWrappedLine(const std::string_view line, float scale, int baseline, std::uint_fast32_t startY, Pixel_BU8_GU8_RU8_AU8 color, Font& font, TextAlignment alignment) {
    // Calculate line width
    std::uint_fast32_t lineWidth = 0;
    std::vector<int> lineAdvances;
    for (const char c : line) {
        int advance, lsb;
        stbtt_GetCodepointHMetrics(&font.font, c, &advance, &lsb);
        lineAdvances.push_back(advance);
        lineWidth += (int)(advance * scale);
    }
    
    // Determine horizontal position based on alignment
    int startX = 0;
    switch (alignment) {
        case TextAlignment::Left:
            startX = 0;
            break;
        case TextAlignment::Center:
            startX = (scaled.width - lineWidth) / 2;
            break;
        case TextAlignment::Right:
            startX = scaled.width - lineWidth;
            break;
    }
    
    // Render the line
    int x = startX;
    int currentY = startY + baseline;
    
    for (std::size_t i = 0; i < line.size(); ++i) {
        int codepoint = line[i];
        
        int ax;
        int lsb;
        stbtt_GetCodepointHMetrics(&font.font, codepoint, &ax, &lsb);

        int c_x1, c_y1, c_x2, c_y2;
        stbtt_GetCodepointBitmapBox(&font.font, codepoint, scale, scale, &c_x1, &c_y1, &c_x2, &c_y2);

        int w = c_x2 - c_x1;
        int h = c_y2 - c_y1;

        std::vector<unsigned char> bitmap(w * h);
        stbtt_MakeCodepointBitmap(&font.font, bitmap.data(), w, h, w, scale, scale, codepoint);

        // Only render characters that fit within the scaled bounds
        for (int j = 0; j < h; j++) {
            for (int i = 0; i < w; i++) {
                int bufferX = x + i + c_x1;
                int bufferY = currentY + j + c_y1;
                
                // Only draw pixels that are within our scaled buffer bounds
                if (bufferX >= 0 && bufferX < (int)scaled.width && bufferY >= 0 && bufferY < (int)scaled.height) {
                    bufferScaled[bufferY * scaled.width + bufferX] = {color.r, color.g, color.b, bitmap[j * w + i]};
                }
            }
        }

        x += (int)(ax * scale);

        if (i + 1 < line.size()) {
            x += (int)stbtt_GetCodepointKernAdvance(&font.font, codepoint, line[i+1]);
        }
    }
}