C++ pdf库总结

mupdf

cpp 复制代码

#include "widget.h"
#include "ui_widget.h"
#include <QMessageBox>
#include <QDebug>
#include <QImage>
#include <QPixmap>
#include <QLabel>
 
#include "mupdf/fitz.h"
#include "mupdf/pdf.h"
 
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
 
    char *input = const_cast< char* >("document.pdf");
    float zoom, rotate;
    int page_number, page_count;
    fz_context *ctx;
    fz_document *doc;
    fz_pixmap *pix;
    fz_matrix ctm;//第一页为0
    page_number=0;
    //100%缩放比
    zoom=;
    //旋转为0
    rotate=;
 
    //创建上下文
    ctx = fz_new_context(NULL, NULL, FZ_STORE_UNLIMITED);
    if (!ctx)
    {
        qDebug()<<stderr<<"cannot create mupdf context";
        return;
    }
 
    //注册文档控制
    fz_try(ctx)
            fz_register_document_handlers(ctx);
    fz_catch(ctx)
    {
        qDebug()<<stderr<<"cannot register document handlers:"<< fz_caught_message(ctx);
        fz_drop_context(ctx);
        return;
    }
 
    //打开文档
    fz_try(ctx)
        doc = fz_open_document(ctx, input);
    fz_catch(ctx)
    {
        qDebug()<<stderr<< "cannot open document:"<< fz_caught_message(ctx);
        fz_drop_context(ctx);
        return;
    }
 
    //取得总的页数
    fz_try(ctx)
        page_count = fz_count_pages(ctx, doc);
    fz_catch(ctx)
    {
        qDebug()<<stderr<< "cannot count number of pages:"<< fz_caught_message(ctx);
        fz_drop_document(ctx, doc);
        fz_drop_context(ctx);
        return;
    }
 
    if (page_number <  || page_number >= page_count)
    {
        qDebug()<<stderr<< "page number out of range: "<< page_number + <<"page count:"<<page_count;
        fz_drop_document(ctx, doc);
        fz_drop_context(ctx);
        return;
    }
 
    //计算缩放以及旋转
    fz_scale(&ctm, zoom / , zoom / );
    fz_pre_rotate(&ctm, rotate);
 
    //渲染pixmap
    fz_try(ctx)
        pix = fz_new_pixmap_from_page_number(ctx, doc, page_number, &ctm, fz_device_rgb(ctx), );
    fz_catch(ctx)
    {
        qDebug()<<stderr<< "cannot render page: %s\n"<< fz_caught_message(ctx);
        fz_drop_document(ctx, doc);
        fz_drop_context(ctx);
        return;
    }
 
    //渲染成图片
//   unsigned char *samples = fz_pixmap_samples(ctx, pix);
       unsigned char *samples = pix->samples;
   int width = fz_pixmap_width(ctx, pix);
   int height = fz_pixmap_height(ctx, pix);
 
   QImage image(samples, width, height,pix->stride,QImage::Format_RGB888); QLabel *label=new QLabel; label->setPixmap(QPixmap::fromImage(image)); ui->layout->addWidget(label); // if (!image.save("a.png")) { // return; // } //回收内存  fz_drop_pixmap(ctx, pix); fz_drop_document(ctx, doc); fz_drop_context(ctx); } Widget::~Widget() { delete ui; }

pdfium

cpp 复制代码

#include "src/pdfium_aux.h"
#include <iostream>
#include <filesystem>

int main(int argc, char* argv[]) 
{
	try {
		RenderPdfOptions options(argc, argv);
		if (options.invalid()) {
			std::cout << "usage:\nrender_pdf.exe inputfile.pdf [output_file.png]" << std::endl;
			return -1;
		}
		InitPdfium(options);
		ScopedFPDFDocument doc(FPDF_LoadDocument(options.inputFile().c_str(), options.password().c_str()));

		std::cout << "rendering " << std::filesystem::path(options.inputFile()).filename() << "...\n";

		auto[from_page_index, to_page_index] = options.range().get(doc.get());
		int num_pages = to_page_index - from_page_index + 1;
		for (auto index = from_page_index; index <= to_page_index; index++) {

			ScopedFPDFPage page(FPDF_LoadPage(doc.get(), index));
			auto bitmap = RenderPage(page.get(), options.scale());
			auto out_filename = options.outputFile( (num_pages > 1) ? std::optional<int>(index) : std::nullopt);
			WriteImage( bitmap.get(), options.imageFormat(), out_filename );
			std::cout << "    generated " << std::filesystem::path(out_filename).filename() << ".\n";
		}
		std::cout << "complete.\n";
	} catch (std::runtime_error e) {
		std::cout << "error: " << e.what() << std::endl;
		return -1;
	} catch (...) {
		std::cout << "error: unkown fatal error occurred" << std::endl;
		return -1;
	}

	return 0;
}

popper

cpp 复制代码

#include "widget.h"
#include <QDebug>
 
 
 
 
Widget::Widget(QWidget *parent)
    : QWidget(parent),
      Cur_Page(0)
{
    int numPages = 0;
    scale = 1;
 
    document = poppler::document::load_from_file("a.pdf");
 
    Total_page = document->pages();
    qDebug() << "PDF pages: " << numPages;
 
 
 
    label = new QLabel(this);
    label->setGeometry(0,0,1024,600);
 
 
    label->setAlignment(Qt::AlignCenter);
    //label->setPixmap(QPixmap::fromImage(qimage));
    label->setVisible(true);
 
    QPushButton* prevBtn = new QPushButton(this);
    prevBtn->setText("Prev");
    prevBtn->setGeometry(910, 240, 60,100);
    connect( prevBtn, SIGNAL(pressed()), this, SLOT(onPrev()));
    QPushButton* nextBtn = new QPushButton(this);
    nextBtn->setText("Next");
    nextBtn->setGeometry(910, 340, 60,100);
    connect( nextBtn, SIGNAL(pressed()), this, SLOT(onNext()));
 
 
    QPushButton* plusBtn = new QPushButton(this);
    plusBtn->setText("+");
    plusBtn->setGeometry(910, 50, 20, 20);
    connect( plusBtn, SIGNAL(pressed()), this, SLOT(onZoomIn()));
    QPushButton* minBtn = new QPushButton(this);
    minBtn->setText("-");
    minBtn->setGeometry(940, 50, 20, 20);
    connect( minBtn, SIGNAL(pressed()), this, SLOT(onZoomOut()));
    updatePage();
 
}
 
Widget::~Widget()
{
 
}
 
void Widget::resizeEvent(QResizeEvent *event)
{
    this->setGeometry(0,0,1024,600);
}
 
 
void Widget::updatePage()
{
    poppler::page_renderer* render = new poppler::page_renderer();
    //render->set_render_hint(poppler::page_renderer::render_hint::antialiasing);
    //render->set_render_hint(poppler::page_renderer::render_hint::text_antialiasing);
 
 
    render->set_render_hints(poppler::page_renderer::render_hint::antialiasing |
                             poppler::page_renderer::render_hint::text_antialiasing
                             );
 
    poppler::page* page = document->create_page(Cur_Page);
 
    poppler::image image = render->render_page(page, 72, 72, -1,-1,-1, -1);
    qDebug() << "image format: " << image.format();
 
    int width = render->render_page(page).width();
    int height = render->render_page(page).height();
    qDebug() << "width: " << width;
    qDebug() << "height: " << height;
 
    qDebug()<< "scale: "<< scale * 100 << "\%";
    QImage qimage((uchar*)image.data(), width, height, QImage::Format::Format_ARGB32);
    qDebug() << "image format: "<<qimage.format();
    label->setPixmap(QPixmap::fromImage(qimage.scaledToWidth(width*scale)));
 
}
 
 
void Widget::onPrev()
{
    if(Cur_Page == 0)
        Cur_Page = 0;
    else
        Cur_Page--;
   //load page
    updatePage();
}
 
void Widget::onNext()
{
    if(Cur_Page == Total_page -1)
        Cur_Page = Total_page -1;
    else
        Cur_Page++;
    //load page
    updatePage();
}
 
void Widget::onZoomIn()
{
    scale += 0.15;
    updatePage();
}
 
void Widget::onZoomOut()
{
    scale -= 0.15;
    updatePage();
}