WIP: Add "Preserve Text (Searchable)" option with full color inversion

Copilot commented

2025-11-29 10:21:17 -05:00

(Migrated from github.com)

Current conversion rasterizes pages to images, breaking Ctrl+F text search. This adds an optional mode that inverts colors while preserving the original PDF text/vector content, keeping text searchable.

Changes

New checkbox option: "Preserve Text (Searchable)" in the controls area (disabled by default)
New checkbox option: "Invert Images" (only visible when Preserve Text is enabled, checked by default)
renderPDFPreserveText(): Uses PDF blend modes to invert colors while preserving text searchability
Refactored existing logic into renderPDFRasterized() for the default inversion mode

The preserve text mode uses PDF "Difference" blend mode to properly invert colors:

White background → Theme color (dark background)
Black text → White/light text (readable on dark background)
All content remains searchable with Ctrl+F

// Create ExtGState for Difference blend mode (for inversion)
const differenceGsDict = pdfDoc.context.obj({
    Type: PDFLib.PDFName.of('ExtGState'),
    BM: PDFLib.PDFName.of('Difference'),
});

// Invert everything by drawing white with Difference blend
contentOps += `q /GSDiff gs 1 1 1 rg 0 0 ${width} ${height} re f Q `;
// Add theme color tint
contentOps += `q /GSDiff gs ${tintR} ${tintG} ${tintB} rg 0 0 ${width} ${height} re f Q `;

Fixes chizkiyahu/pdf-dark-mode-converter#12

Original prompt

This section details on the original issue you should resolve

<issue_title>ctrl-f no words found?</issue_title>
<issue_description>Want to thank you because I really like the dark pdf, and the datasheets are so much easier on the eyes late at night, but a little hard to find things since the the browser search seems to be broken after conversion? Looks like text is converted to raster </issue_description>

<agent_instructions>now the conversion is image
try to change the backgroud without change the image
do it only as an option (not a default) </agent_instructions>

Comments on the Issue (you are @copilot in this section)

Fixes chizkiyahu/pdf-dark-mode-converter#12

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

Current conversion rasterizes pages to images, breaking Ctrl+F text search. This adds an optional mode that inverts colors while preserving the original PDF text/vector content, keeping text searchable. ## Changes - **New checkbox option**: "Preserve Text (Searchable)" in the controls area (disabled by default) - **New checkbox option**: "Invert Images" (only visible when Preserve Text is enabled, checked by default) - **`renderPDFPreserveText()`**: Uses PDF blend modes to invert colors while preserving text searchability - **Refactored existing logic** into `renderPDFRasterized()` for the default inversion mode The preserve text mode uses PDF "Difference" blend mode to properly invert colors: - White background → Theme color (dark background) - Black text → White/light text (readable on dark background) - All content remains searchable with Ctrl+F ```javascript // Create ExtGState for Difference blend mode (for inversion) const differenceGsDict = pdfDoc.context.obj({ Type: PDFLib.PDFName.of('ExtGState'), BM: PDFLib.PDFName.of('Difference'), }); // Invert everything by drawing white with Difference blend contentOps += `q /GSDiff gs 1 1 1 rg 0 0 ${width} ${height} re f Q `; // Add theme color tint contentOps += `q /GSDiff gs ${tintR} ${tintG} ${tintB} rg 0 0 ${width} ${height} re f Q `; ``` <img src="https://github.com/user-attachments/assets/32ab7117-ef64-4c56-82be-89d52529480b"> - Fixes chizkiyahu/pdf-dark-mode-converter#12  <details> <summary>Original prompt</summary> > > ---- > > *This section details on the original issue you should resolve* > > <issue_title>ctrl-f no words found?</issue_title> > <issue_description>Want to thank you because I really like the dark pdf, and the datasheets are so much easier on the eyes late at night, but a little hard to find things since the the browser search seems to be broken after conversion? Looks like text is converted to raster </issue_description> > > <agent_instructions>now the conversion is image > try to change the backgroud without change the image > do it only as an option (not a default) </agent_instructions> > > ## Comments on the Issue (you are @copilot in this section) > > <comments> > </comments> > </details> - Fixes chizkiyahu/pdf-dark-mode-converter#12  --- 💬 We'd love your input! Share your thoughts on Copilot coding agent in our [2 minute survey](https://gh.io/copilot-coding-agent-survey).

chizkiyahu commented

2025-11-29 11:37:14 -05:00

(Migrated from github.com)

@copilot the part of the files bacgorud is still w
and the text is still b in all the backgourd w and b
make sure to replace the bacgroud and the the text
about images have a checkbox to let the user decide if to change or not

@copilot the part of the files bacgorud is still w and the text is still b in all the backgourd w and b make sure to replace the bacgroud and the the text about images have a checkbox to let the user decide if to change or not

Copilot commented

2025-11-29 11:45:44 -05:00

(Migrated from github.com)

@copilot the part of the files bacgorud is still w
and the text is still b in all the backgourd w and b
make sure to replace the bacgroud and the the text ...

Fixed in fb24894. The "Preserve Text" mode now properly inverts colors using PDF blend modes:

White background → Theme color
Black text → White/light text
Added "Invert Images" checkbox (checked by default) to let users choose whether to invert images

> @copilot the part of the files bacgorud is still w > and the text is still b in all the backgourd w and b > make sure to replace the bacgroud and the the text ... Fixed in fb24894. The "Preserve Text" mode now properly inverts colors using PDF blend modes: - White background → Theme color - Black text → White/light text - Added "Invert Images" checkbox (checked by default) to let users choose whether to invert images ![UI Screenshot](https://github.com/user-attachments/assets/32ab7117-ef64-4c56-82be-89d52529480b)

Pull request closed

Please reopen this pull request to perform a merge.

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WIP: Add "Preserve Text (Searchable)" option with full color inversion #13

Changes

Comments on the Issue (you are @copilot in this section)

Pull request closed