Optimize rendering of two dimensional barcodes: deduplicate regions.

Reduce the logical size of the barcode by removing unnecessary
region duplication.

As far as I can tell, the line thickness is useless and the aspect
ratio causes arbitrary changes in rounding, but ultimately the
dimensions of a barcode are defined by its width and height, rather
than by this ratio.

The improvement with this CL is from ~580ms to ~390ms per barcode,
so about 1.5x. Combined with
https://pdfium-review.googlesource.com/c/pdfium/+/40010
the improvement is to ~15ms, which is about 39x.

This also fixes the rendering of the barcode in the pixel and
corpus tests. You can verify this pointing a barcode reader app at
the screen. It does not however fix every case, as the unit test is
still unreadable.

Bug: 872907, pdfium:1135
Change-Id: Ic28e60f54719552cfe69ace7ebc3f730c338a129
Reviewed-on: https://pdfium-review.googlesource.com/40030
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Ryan Harrison <rharrison@chromium.org>

1 files changed, 3 insertions, 6 deletions

diff --git a/fxbarcode/pdf417/BC_PDF417Writer.cpp b/fxbarcode/pdf417/BC_PDF417Writer.cpp
index 4fec974737..026c89a59d 100644
--- a/fxbarcode/pdf417/BC_PDF417Writer.cpp
+++ b/fxbarcode/pdf417/BC_PDF417Writer.cpp
@@ -63,15 +63,13 @@ uint8_t* CBC_PDF417Writer::Encode(const WideString& contents,
   if (!encoder.generateBarcodeLogic(contents, m_iCorrectLevel))
     return nullptr;
 
-  int32_t lineThickness = 2;
-  int32_t aspectRatio = 4;
   CBC_BarcodeMatrix* barcodeMatrix = encoder.getBarcodeMatrix();
-  std::vector<uint8_t> originalScale = barcodeMatrix->getScaledMatrix(
-      lineThickness, aspectRatio * lineThickness);
+  std::vector<uint8_t> originalScale = barcodeMatrix->getMatrix();
   int32_t width = outWidth;
   int32_t height = outHeight;
   outWidth = barcodeMatrix->getWidth();
   outHeight = barcodeMatrix->getHeight();
+
   bool rotated = false;
   if ((height > width) ^ (outWidth < outHeight)) {
     rotateArray(originalScale, outHeight, outWidth);
@@ -84,8 +82,7 @@ uint8_t* CBC_PDF417Writer::Encode(const WideString& contents,
   int32_t scaleY = height / outHeight;
   int32_t scale = std::min(scaleX, scaleY);
   if (scale > 1) {
-    originalScale = barcodeMatrix->getScaledMatrix(
-        scale * lineThickness, scale * aspectRatio * lineThickness);
+    originalScale = barcodeMatrix->getScaledMatrix(scale);
     if (rotated) {
       rotateArray(originalScale, outHeight, outWidth);
       int32_t temp = outHeight;