floating_label.cpp

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/*
    Copyright (C) 2003 - 2025
    by David White <dave@whitevine.net>
    Part of the Battle for Wesnoth Project https://www.wesnoth.org/
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY.
 
    See the COPYING file for more details.
*/
 
#include "floating_label.hpp"
 
#include "draw.hpp"
#include "draw_manager.hpp"
#include "font/standard_colors.hpp"
#include "font/text.hpp"
#include "log.hpp"
#include "serialization/chrono.hpp"
#include "video.hpp"
 
#include <map>
#include <set>
#include <stack>
 
static lg::log_domain log_font("font");
#define DBG_FT LOG_STREAM(debug, log_font)
#define LOG_FT LOG_STREAM(info, log_font)
#define WRN_FT LOG_STREAM(warn, log_font)
#define ERR_FT LOG_STREAM(err, log_font)
 
static lg::log_domain log_display("display");
#define ERR_DP LOG_STREAM(err, log_display)
 
namespace
{
typedef std::map<int, font::floating_label> label_map;
label_map labels;
int label_id = 1;
 
std::stack<std::set<int>> label_contexts;
 
}
 
using namespace std::chrono_literals;
 
namespace font
{
floating_label::floating_label(const std::string& text)
    : tex_()
    , screen_loc_()
    , alpha_(0)
    , fadeout_(0)
    , time_start_()
    , text_((!text.empty() && text.back() == '\n') ? std::string(text.begin(), text.end() - 1) : text) // remove unwanted trailing newline
    , font_size_(SIZE_SMALL)
    , color_(NORMAL_COLOR)
    , bgcolor_(0, 0, 0, SDL_ALPHA_TRANSPARENT)
    , xpos_(0)
    , ypos_(0)
    , xmove_(0)
    , ymove_(0)
    , lifetime_(-1)
    , width_(-1)
    , height_(-1)
    , clip_rect_(video::game_canvas())
    , visible_(true)
    , align_(CENTER_ALIGN)
    , border_(0)
    , scroll_(ANCHOR_LABEL_SCREEN)
    , use_markup_(true)
{
}
 
void floating_label::move(double xmove, double ymove)
{
    xpos_ += xmove;
    ypos_ += ymove;
}
 
int floating_label::xpos(std::size_t width) const
{
    int xpos = int(xpos_);
    if(align_ == font::CENTER_ALIGN) {
        xpos -= width / 2;
    } else if(align_ == font::RIGHT_ALIGN) {
        xpos -= width;
    }
 
    return xpos;
}
 
rect floating_label::get_bg_rect(const rect& text_rect) const
{
    return text_rect.padded_by(border_);
}
 
void floating_label::clear_texture()
{
    tex_.reset();
}
 
bool floating_label::create_texture()
{
    if(video::headless()) {
        return false;
    }
 
    if(tex_ != nullptr) {
        // Already have a texture
        return true;
    }
 
    if(text_.empty()) {
        // Empty labels are unfortunately still used sometimes
        return false;
    }
 
    DBG_FT << "creating floating label texture, text: " << text_.substr(0,15);
    font::pango_text& text = font::get_text_renderer();
 
    text.set_link_aware(false)
        .set_family_class(font::family_class::sans_serif)
        .set_font_size(font_size_)
        .set_font_style(font::pango_text::STYLE_NORMAL)
        .set_alignment(PANGO_ALIGN_LEFT)
        .set_foreground_color(color_)
        .set_maximum_width(width_ < 0 ? clip_rect_.w : width_)
        .set_maximum_height(height_ < 0 ? clip_rect_.h : height_, true)
        .set_ellipse_mode(PANGO_ELLIPSIZE_END)
        .set_characters_per_line(0)
        .set_add_outline(bgcolor_.a == 0);
 
    text.set_text(text_, use_markup_);
 
    tex_ = text.render_and_get_texture();
    if(!tex_) {
        ERR_FT << "could not create floating label's text";
        return false;
    }
 
    return true;
}
 
void floating_label::undraw()
{
    DBG_FT << "undrawing floating label from " << screen_loc_;
    draw_manager::invalidate_region(get_bg_rect(screen_loc_));
    screen_loc_ = {};
}
 
void floating_label::update(const clock::time_point& time)
{
    if(video::headless() || text_.empty()) {
        return;
    }
 
    if(!create_texture()) {
        ERR_FT << "failed to create texture for floating label";
        return;
    }
 
    rect draw_loc{get_pos(time), tex_.draw_size()};
    uint8_t new_alpha = get_alpha(time);
 
    // Nothing has changed
    // FIXME: we consider border too since otherwise we get flickering under floating
    // labels with a background (see bug #7700). This isn't ideal for chat messages or
    // tooltips, but it optimizes the usual case (map labels).
    if(screen_loc_ == draw_loc && alpha_ == new_alpha && border_ == 0) {
        return;
    }
 
    // Invalidate former draw loc
    draw_manager::invalidate_region(get_bg_rect(screen_loc_));
 
    // Invalidate new draw loc in preparation
    draw_manager::invalidate_region(get_bg_rect(draw_loc));
 
    DBG_FT << "updating floating label from " << screen_loc_ << " to " << draw_loc;
 
    screen_loc_ = draw_loc;
    alpha_ = new_alpha;
}
 
void floating_label::draw()
{
    if(!visible_) {
        screen_loc_ = {};
        return;
    }
 
    if(screen_loc_.empty()) {
        return;
    }
 
    if(!tex_) {
        ERR_DP << "trying to draw floating label with no texture!";
        return;
    }
 
    if(!screen_loc_.overlaps(draw::get_clip().intersect(clip_rect_))) {
        return;
    }
 
    DBG_FT << "drawing floating label to " << screen_loc_;
 
    // Clip if appropriate.
    auto clipper = draw::reduce_clip(clip_rect_);
 
    // Draw background, if appropriate
    if(bgcolor_.a != 0) {
        draw::fill(get_bg_rect(screen_loc_), bgcolor_);
    }
 
    // Apply the label texture to the screen.
    tex_.set_alpha_mod(alpha_);
    draw::blit(tex_, screen_loc_);
}
 
void floating_label::set_lifetime(const std::chrono::milliseconds& lifetime, const std::chrono::milliseconds& fadeout)
{
    lifetime_ = lifetime;
    fadeout_ = fadeout;
    time_start_ = std::chrono::steady_clock::now();
}
 
auto floating_label::get_time_alive(const clock::time_point& current_time) const -> clock::duration
{
    return current_time - time_start_;
}
 
point floating_label::get_pos(const clock::time_point& time) const
{
    double new_x = xpos(tex_.w());
    double new_y = ypos_;
 
    if(xmove_ != 0.0 || ymove_ != 0.0) {
        auto time_alive = std::chrono::duration_cast<std::chrono::milliseconds>(get_time_alive(time));
        new_x += time_alive.count() * xmove_;
        new_y += time_alive.count() * ymove_;
    }
 
    // TODO: return a floating point point
    return {static_cast<int>(new_x), static_cast<int>(new_y)};
}
 
uint8_t floating_label::get_alpha(const clock::time_point& time) const
{
    if(lifetime_ >= 0ms && fadeout_ > 0ms) {
        auto time_alive = get_time_alive(time);
        if(time_alive >= lifetime_) {
            double progress = chrono::normalize_progress(time_alive - lifetime_, fadeout_);
            return float_to_color(1.0 - progress);
        }
    }
    return ALPHA_OPAQUE;
}
 
int add_floating_label(const floating_label& flabel)
{
    if(label_contexts.empty()) {
        return 0;
    }
 
    ++label_id;
    labels.emplace(label_id, flabel);
    label_contexts.top().insert(label_id);
    return label_id;
}
 
void move_floating_label(int handle, double xmove, double ymove)
{
    const label_map::iterator i = labels.find(handle);
    if(i != labels.end()) {
        i->second.move(xmove, ymove);
    }
}
 
void scroll_floating_labels(double xmove, double ymove)
{
    for(auto& [id, label] : labels) {
        if(label.scroll() == ANCHOR_LABEL_MAP) {
            label.move(xmove, ymove);
        }
    }
}
 
void remove_floating_label(int handle, const std::chrono::milliseconds& fadeout)
{
    const label_map::iterator i = labels.find(handle);
    if(i != labels.end()) {
        if(fadeout > 0ms) {
            i->second.set_lifetime(0ms, fadeout);
            return;
        } else if(fadeout < 0ms) {
            i->second.set_lifetime(0ms, i->second.get_fade_time());
            return;
        }
        // Queue a redraw of where the label was.
        i->second.undraw();
        labels.erase(i);
    }
 
    if(!label_contexts.empty()) {
        label_contexts.top().erase(handle);
    }
}
 
void show_floating_label(int handle, bool value)
{
    const label_map::iterator i = labels.find(handle);
    if(i != labels.end()) {
        i->second.show(value);
    }
}
 
rect get_floating_label_rect(int handle)
{
    const label_map::iterator i = labels.find(handle);
    if(i != labels.end()) {
        if (i->second.create_texture()) {
            point size = i->second.get_draw_size();
            return {0, 0, size.x, size.y};
        }
    }
    return {};
}
 
floating_label_context::floating_label_context()
{
    // hacky but the whole floating label system needs to be redesigned...
    for(auto& [id, label] : labels) {
        if(label_contexts.top().count(id) > 0) {
            label.undraw();
        }
    }
 
    //TODO: 'pause' floating labels in other contexrs
    label_contexts.emplace();
}
 
floating_label_context::~floating_label_context()
{
    //TODO: 'pause' floating labels in other contexrs
    const std::set<int>& context = label_contexts.top();
 
    while(!context.empty()) {
        // Remove_floating_label removes the passed label from the context.
        // This loop removes a different label in every iteration.
        remove_floating_label(*context.begin());
    }
 
    label_contexts.pop();
}
 
void draw_floating_labels()
{
    if(label_contexts.empty()) {
        return;
    }
 
    const std::set<int>& context = label_contexts.top();
 
    // draw the labels in the order they were added, so later added labels (likely to be tooltips)
    // are displayed over earlier added labels.
    for(auto& [id, label] : labels) {
        if(context.count(id) > 0) {
            label.draw();
        }
    }
}
 
void update_floating_labels()
{
    if(label_contexts.empty()) {
        return;
    }
 
    auto time = std::chrono::steady_clock::now();
    std::set<int>& context = label_contexts.top();
 
    for(auto iter = labels.begin(); iter!= labels.end();) {
        auto& [id, label] = *iter;
 
        if(context.count(id) > 0) {
            label.update(time);
 
            if(label.expired(time)) {
                context.erase(id);
                iter = labels.erase(iter);
                continue;
            }
        }
 
        ++iter;
    }
}
 
}