Foxit Developer

Redaction ​

Redaction annotations permanently remove or obscure sensitive PDF content. Unlike other annotations, redaction has mark and apply phases: marking previews the effect; apply permanently removes content under the marked areas.

Important

After apply, content under redacted areas is permanently removed and cannot be recovered. Back up the document before applying.

Workflow ​

  1. Create — Add Redact annotation over target area
  2. Configure — Overlay color, text, etc.
  3. Preview — Original content remains until apply
  4. Apply — Permanently remove content; annotations are removed

Core methods ​

MethodDescription
getQuadPoints / setQuadPoints:Redaction region (precise text areas)
getFillColor / setFillColor:Mark-phase fill (preview)
getApplyFillColor / setApplyFillColor:Fill after apply
getOverlayText / setOverlayText:Overlay text after apply
isOverlayTextRepeated / enableRepeatOverlayText:Repeat overlay text
getOverlayTextAlignment / setOverlayTextAlignment:Overlay alignment
getDefaultAppearance / setDefaultAppearance:Overlay font appearance
enableAutoFontSizeAuto-fit overlay font size
applyApply redaction — permanent removal

Example: create and apply ​

objc
#import <FoxitRDK/FSPDFObjC.h>

FSPDFDoc *doc = [[FSPDFDoc alloc] initWithPath:@"path/to/Sample.pdf"];
[doc load:nil];
FSPDFPage *page = [doc getPage:0];

FSRectF *rect = [[FSRectF alloc] initWithLeft1:100 bottom1:700 right1:350 top1:720];
FSAnnot *annot = [page addAnnot:FSAnnotRedact rect:rect];
FSRedact *redact = [[FSRedact alloc] initWithAnnot:annot];

[redact setFillColor:0xFFFF0000];
[redact setApplyFillColor:0xFF000000];

[redact setOverlayText:@"已脱敏"];
[redact setOverlayTextAlignment:1];

FSDefaultAppearance *da = [[FSDefaultAppearance alloc] init];
[da setText_size:12];
[da setText_color:0xFFFFFFFF];
[redact setDefaultAppearance:da];

[redact resetAppearanceStream];

[doc saveAs:@"path/to/preview.pdf" saveFlags:FSPDFDocSaveFlagNormal];

[redact apply];
[doc saveAs:@"path/to/redacted.pdf" saveFlags:FSPDFDocSaveFlagNormal];

Example: precise text redaction ​

Combine text search with QuadPoints:

objc
#import <FoxitRDK/FSPDFObjC.h>

FSTextSearch *textSearch = [[FSTextSearch alloc] initWithDocument:doc cancel_callback:nil];
[textSearch setPattern:@"机密信息"];

if ([textSearch findNext]) {
    FSRectFArray *rects = [textSearch getMatchRects];

    FSQuadPointsArray *quadPointsArray = [[FSQuadPointsArray alloc] init];
    for (int i = 0; i < [rects getSize]; i++) {
        FSRectF *r = [rects getAt:i];
        FSQuadPoints *qp = [[FSQuadPoints alloc] init];
        FSPointF *first = [[FSPointF alloc] init];
        [first set:[r getLeft] y:[r getTop]];
        FSPointF *second = [[FSPointF alloc] init];
        [second set:[r getRight] y:[r getTop]];
        FSPointF *third = [[FSPointF alloc] init];
        [third set:[r getLeft] y:[r getBottom]];
        FSPointF *fourth = [[FSPointF alloc] init];
        [fourth set:[r getRight] y:[r getBottom]];
        [qp setFirst:first];
        [qp setSecond:second];
        [qp setThird:third];
        [qp setFourth:fourth];
        [quadPointsArray add:qp];
    }

    FSRectF *emptyRect = [[FSRectF alloc] initWithLeft1:0 bottom1:0 right1:0 top1:0];
    FSAnnot *annot = [page addAnnot:FSAnnotRedact rect:emptyRect];
    FSRedact *redact = [[FSRedact alloc] initWithAnnot:annot];
    [redact setQuadPoints:quadPointsArray];
    [redact setApplyFillColor:0xFF000000];
    [redact resetAppearanceStream];

    [redact apply];
}