github.com/pdfcpu/pdfcpu@v0.11.1/pkg/api/zoom.go (about)

     1  /*
     2  Copyright 2024 The pdfcpu Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8  	http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package api
    18  
    19  import (
    20  	"io"
    21  	"os"
    22  
    23  	"github.com/pdfcpu/pdfcpu/pkg/log"
    24  	"github.com/pdfcpu/pdfcpu/pkg/pdfcpu"
    25  	"github.com/pdfcpu/pdfcpu/pkg/pdfcpu/model"
    26  	"github.com/pkg/errors"
    27  )
    28  
    29  // Zoom applies resizeConf for selected pages of rs and writes result to w.
    30  func Zoom(rs io.ReadSeeker, w io.Writer, selectedPages []string, zoom *model.Zoom, conf *model.Configuration) error {
    31  	if rs == nil {
    32  		return errors.New("pdfcpu: Zoom: missing rs")
    33  	}
    34  
    35  	if conf == nil {
    36  		conf = model.NewDefaultConfiguration()
    37  	}
    38  	conf.Cmd = model.ZOOM
    39  
    40  	ctx, err := ReadValidateAndOptimize(rs, conf)
    41  	if err != nil {
    42  		return err
    43  	}
    44  
    45  	pages, err := PagesForPageSelection(ctx.PageCount, selectedPages, true, true)
    46  	if err != nil {
    47  		return err
    48  	}
    49  
    50  	if err = pdfcpu.Zoom(ctx, pages, zoom); err != nil {
    51  		return err
    52  	}
    53  
    54  	return Write(ctx, w, conf)
    55  }
    56  
    57  // ZoomFile applies zoomConf for selected pages of inFile and writes result to outFile.
    58  func ZoomFile(inFile, outFile string, selectedPages []string, zoom *model.Zoom, conf *model.Configuration) (err error) {
    59  	if log.CLIEnabled() {
    60  		log.CLI.Printf("zooming %s\n", inFile)
    61  	}
    62  
    63  	tmpFile := inFile + ".tmp"
    64  	if outFile != "" && inFile != outFile {
    65  		tmpFile = outFile
    66  		logWritingTo(outFile)
    67  	} else {
    68  		logWritingTo(inFile)
    69  	}
    70  
    71  	var (
    72  		f1, f2 *os.File
    73  	)
    74  
    75  	if f1, err = os.Open(inFile); err != nil {
    76  		return err
    77  	}
    78  
    79  	if f2, err = os.Create(tmpFile); err != nil {
    80  		f1.Close()
    81  		return err
    82  	}
    83  
    84  	defer func() {
    85  		if err != nil {
    86  			f2.Close()
    87  			f1.Close()
    88  			os.Remove(tmpFile)
    89  			return
    90  		}
    91  		if err = f2.Close(); err != nil {
    92  			return
    93  		}
    94  		if err = f1.Close(); err != nil {
    95  			return
    96  		}
    97  		if outFile == "" || inFile == outFile {
    98  			err = os.Rename(tmpFile, inFile)
    99  		}
   100  	}()
   101  
   102  	if conf == nil {
   103  		conf = model.NewDefaultConfiguration()
   104  	}
   105  	conf.Cmd = model.ZOOM
   106  
   107  	return Zoom(f1, f2, selectedPages, zoom, conf)
   108  }