[Libreoffice-commits] core.git: vcl/source

[Caolán McNamara (via logerrit)]

 vcl/source/filter/png/PngImageReader.cxx |   19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

New commits:
commit 31913141d2bcc3b3a8bfb6d018fbf142bd81bf58
Author:     Caolán McNamara <caolanm at redhat.com>
AuthorDate: Mon Mar 22 20:31:01 2021 +0000
Commit:     Caolán McNamara <caolanm at redhat.com>
CommitDate: Wed Mar 24 16:22:00 2021 +0100

    Related: ofz#32152
    
    use scanline as buffer and postprocess to premultiply (optionally
    relocating alpha)
    
    Change-Id: Ib279429873392b97901294191688b24867dcf450
    Reviewed-on: https://gerrit.libreoffice.org/c/core/+/112942
    Tested-by: Jenkins
    Reviewed-by: Caolán McNamara <caolanm at redhat.com>

diff --git a/vcl/source/filter/png/PngImageReader.cxx b/vcl/source/filter/png/PngImageReader.cxx
index ce168ef13c9e..cdb90d93940a 100644
--- a/vcl/source/filter/png/PngImageReader.cxx
+++ b/vcl/source/filter/png/PngImageReader.cxx
@@ -230,10 +230,6 @@ bool reader(SvStream& rStream, BitmapEx& rBitmapEx, bool bUseBitmap32)
                         png_set_bgr(pPng);
                     }
 
-                    aRows = std::vector<std::vector<png_byte>>(height);
-                    for (auto& rRow : aRows)
-                        rRow.resize(aRowSizeBytes, 0);
-
                     auto const alphaFirst = (eFormat == ScanlineFormat::N32BitTcAbgr
                                              || eFormat == ScanlineFormat::N32BitTcArgb);
                     for (int pass = 0; pass < nNumberOfPasses; pass++)
@@ -241,19 +237,22 @@ bool reader(SvStream& rStream, BitmapEx& rBitmapEx, bool bUseBitmap32)
                         for (png_uint_32 y = 0; y < height; y++)
                         {
                             Scanline pScanline = pWriteAccess->GetScanline(y);
-                            png_bytep pRow = aRows[y].data();
-                            png_read_row(pPng, pRow, nullptr);
+                            png_read_row(pPng, pScanline, nullptr);
                             size_t iColor = 0;
                             for (size_t i = 0; i < aRowSizeBytes; i += 4)
                             {
-                                sal_Int8 alpha = pRow[i + 3];
+                                sal_uInt8 alpha = pScanline[i + 3];
+                                sal_uInt8 byte1 = vcl::bitmap::premultiply(pScanline[i + 0], alpha);
+                                sal_uInt8 byte2 = vcl::bitmap::premultiply(pScanline[i + 1], alpha);
+                                sal_uInt8 byte3 = vcl::bitmap::premultiply(pScanline[i + 2], alpha);
+
                                 if (alphaFirst)
                                 {
                                     pScanline[iColor++] = alpha;
                                 }
-                                pScanline[iColor++] = vcl::bitmap::premultiply(pRow[i + 0], alpha);
-                                pScanline[iColor++] = vcl::bitmap::premultiply(pRow[i + 1], alpha);
-                                pScanline[iColor++] = vcl::bitmap::premultiply(pRow[i + 2], alpha);
+                                pScanline[iColor++] = byte1;
+                                pScanline[iColor++] = byte2;
+                                pScanline[iColor++] = byte3;
                                 if (!alphaFirst)
                                 {
                                     pScanline[iColor++] = alpha;