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// -*- mode: c++; c-basic-offset: 4; indent-tabs-mode: nil; -*-
// (c) 2020 Henner Zeller <h.zeller@acm.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 version 2.
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://gnu.org/licenses/gpl-2.0.txt>
#include "renderer.h"
#include <string.h>
#include <unistd.h>
#include <memory>
namespace timg {
std::string Renderer::TrimTitle(const std::string &title,
int requested_width) const {
std::string result = title;
// Columns can be too narrow. We might need to trim what we print.
if ((int)result.length() > requested_width) {
result.replace(0, result.length() - requested_width + 3, "...");
}
else if (options_.center_horizontally) {
const int start_spaces = (requested_width - result.length()) / 2;
result.insert(0, std::string(start_spaces, ' '));
}
result += "\n";
return result;
}
namespace {
// Use the full canvas to display framebuffer; writes framebuffer directly.
class SingleColumnRenderer final : public Renderer {
public:
SingleColumnRenderer(timg::TerminalCanvas *canvas,
const DisplayOptions &display_opts, Duration wait_time)
: Renderer(canvas, display_opts), wait_time_(wait_time) {}
WriteFramebufferFun render_cb(const std::string &title) final {
// For single column mode, implementation is straightforward
RenderTitle(title);
return [this](int x, int dy, const Framebuffer &fb, SeqType seq_type,
const Duration &end_of_frame) {
canvas_->Send(x, dy, fb, seq_type, end_of_frame);
};
}
void MaybeWaitBetweenImageSources() const final {
if (!wait_time_.is_zero()) {
(Time::Now() + wait_time_).WaitUntil();
}
}
private:
void RenderTitle(const std::string &title) {
if (!options_.show_title) return;
const std::string tout =
TrimTitle(title, options_.width / options_.cell_x_px);
canvas_->AddPrefixNextSend(tout.data(), tout.size());
}
const Duration wait_time_;
};
// The multi column renderer positions every update in a new column.
// It keeps track which column it is in and if a new row needs to be started
// and uses cursor movements to get to the right place.
class MultiColumnRenderer final : public Renderer {
public:
MultiColumnRenderer(timg::TerminalCanvas *canvas,
const DisplayOptions &display_opts, int cols, int rows,
Duration wait_between_images,
Duration wait_between_rows)
: Renderer(canvas, display_opts),
columns_(cols),
column_width_(display_opts.width),
wait_between_images_(wait_between_images),
wait_between_rows_(wait_between_rows) {}
~MultiColumnRenderer() final {
if (current_column_ != 0) {
const int down = highest_fb_column_height_ - last_fb_height_;
if (down > 0) {
canvas_->MoveCursorDY(down / options_.cell_y_px);
}
}
}
WriteFramebufferFun render_cb(const std::string &title) final {
AdvanceColumn();
PrepareTitle(title);
first_render_call_ = true;
return [this](int x, int dy, const Framebuffer &fb, SeqType seq_type,
const Duration &end_of_frame) {
int y_offset;
if (first_render_call_) {
// Unless we're in the first column, we've to move up from last
y_offset = current_column_ > 0 ? -last_fb_height_ : 0;
}
else {
if (dy != 0) {
y_offset = dy; // Some animation jumping back
}
else {
// Multi-image rendering, shown in multiple columns.
y_offset = AdvanceColumn() ? 0 : -last_fb_height_;
}
}
const int x_offset = current_column_ * column_width_;
if (options_.show_title && first_render_call_) {
// If we have to show the headline, we've to do the move up
// before Send() would do it.
// We need to move one more up to be in the 'headline' ypos
if (y_offset) {
// Move pixels needed for cell, then one more
// then one line more to reach the place of the title.
const int y_move =
canvas_->cell_height_for_pixels(y_offset);
const int kSpaceForTitle = 1;
canvas_->MoveCursorDY(y_move - kSpaceForTitle);
}
canvas_->MoveCursorDX(x_offset / options_.cell_x_px);
canvas_->AddPrefixNextSend(title_.c_str(), title_.length());
y_offset = 0; // No move by Send() needed anymore.
}
canvas_->Send(x + x_offset, y_offset, fb, seq_type, end_of_frame);
last_fb_height_ = fb.height();
if (last_fb_height_ > highest_fb_column_height_)
highest_fb_column_height_ = last_fb_height_;
first_render_call_ = false;
};
}
void MaybeWaitBetweenImageSources() const final {
if (!wait_between_images_.is_zero()) {
(Time::Now() + wait_between_images_).WaitUntil();
}
if (current_column_ == columns_ - 1 && !wait_between_rows_.is_zero()) {
(Time::Now() + wait_between_rows_).WaitUntil();
}
}
private:
void PrepareTitle(const std::string &title) {
if (!options_.show_title) return;
title_ = TrimTitle(title, column_width_ / options_.cell_x_px);
}
bool AdvanceColumn() {
++current_column_;
if (current_column_ >= columns_) {
// If our current image is shorter than the previous one,
// we need to make up the difference to be ready for the next
const int down = highest_fb_column_height_ - last_fb_height_;
if (down > 0) canvas_->MoveCursorDY(down);
current_column_ = 0;
highest_fb_column_height_ = 0;
return true;
}
return false;
}
const int columns_;
const int column_width_;
const Duration wait_between_images_;
const Duration wait_between_rows_;
std::string title_;
bool first_render_call_ = true;
int current_column_ = -1;
int highest_fb_column_height_ = 0; // maximum seen in this row
int last_fb_height_ = 0;
};
} // namespace
Renderer::Renderer(timg::TerminalCanvas *canvas,
const DisplayOptions &display_opts)
: canvas_(canvas), options_(display_opts) {}
std::unique_ptr<Renderer> Renderer::Create(timg::TerminalCanvas *output,
const DisplayOptions &display_opts,
int cols, int rows,
Duration wait_between_images,
Duration wait_between_rows) {
if (cols > 1) {
return std::make_unique<MultiColumnRenderer>(output, display_opts, cols,
rows, wait_between_images,
wait_between_rows);
}
return std::make_unique<SingleColumnRenderer>(
output, display_opts, std::max(wait_between_images, wait_between_rows));
}
} // namespace timg
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