Fix incorrect alpha-blend in some cases.

[dcpomatic.git] / src / lib / image.cc

diff --git a/src/lib/image.cc b/src/lib/image.cc
index c3955c92add136e25accc3ff2e5aa9ea36cb81fd..33a0077db8e40d49bc40902a6c5879b4bba69e3d 100644 (file)
--- a/src/lib/image.cc
+++ b/src/lib/image.cc
@@ -68,15 +68,16 @@ Image::vertical_factor (int n) const
 int
 Image::horizontal_factor (int n) const
 {
-       int horizontal_factor = 1;
-       if (n > 0) {
-               AVPixFmtDescriptor const * d = av_pix_fmt_desc_get (_pixel_format);
-               if (!d) {
-                       throw PixelFormatError ("sample_size()", _pixel_format);
-               }
-               horizontal_factor = pow (2.0f, d->log2_chroma_w);
+       if (n == 0) {
+               return 1;
        }
-       return horizontal_factor;
+
+       AVPixFmtDescriptor const * d = av_pix_fmt_desc_get(_pixel_format);
+       if (!d) {
+               throw PixelFormatError ("sample_size()", _pixel_format);
+       }
+
+       return pow (2.0f, d->log2_chroma_w);
 }
 
 /** @param n Component index.
@@ -204,7 +205,7 @@ Image::crop_scale_window (
 
        uint8_t* scale_out_data[out->planes()];
        for (int c = 0; c < out->planes(); ++c) {
-               scale_out_data[c] = out->data()[c] + lrintf (out->bytes_per_pixel(c) * corner.x) + out->stride()[c] * corner.y;
+               scale_out_data[c] = out->data()[c] + lrintf (out->bytes_per_pixel(c) * corner.x) + out->stride()[c] * (corner.y / out->vertical_factor(c));
        }
 
        sws_scale (
@@ -219,6 +220,12 @@ Image::crop_scale_window (
        return out;
 }
 
+shared_ptr<Image>
+Image::convert_pixel_format (dcp::YUVToRGB yuv_to_rgb, AVPixelFormat out_format, bool out_aligned, bool fast) const
+{
+       return scale(size(), yuv_to_rgb, out_format, out_aligned, fast);
+}
+
 /** @param out_size Size to scale to.
  *  @param yuv_to_rgb YUVToRGB transform transform to use, if required.
  *  @param out_format Output pixel format.
@@ -442,19 +449,23 @@ component (
 {
        dcp::Size const base_size = base->sample_size(n);
        dcp::Size const other_size = other->sample_size(n);
-       for (int by = start_base_y, oy = start_other_y; by < base_size.height && oy < other_size.height; ++by, ++oy) {
+       int const bhf = base->horizontal_factor(n);
+       int const bvf = base->vertical_factor(n);
+       int const ohf = other->horizontal_factor(n);
+       int const ovf = other->vertical_factor(n);
+       for (int by = start_base_y / bvf, oy = start_other_y / ovf, ry = start_other_y; by < base_size.height && oy < other_size.height; ++by, ++oy, ry += ovf) {
                /* base image */
-               T* bp = ((T*) (base->data()[n] + by * base->stride()[n])) + start_base_x;
+               T* bp = ((T*) (base->data()[n] + by * base->stride()[n])) + start_base_x / bhf;
                /* overlay image */
                T* op = ((T*) (other->data()[n] + oy * other->stride()[n]));
                /* original RGBA for alpha channel */
-               uint8_t* rp = rgba->data()[0] + oy * rgba->stride()[0];
-               for (int bx = start_base_x, ox = start_other_x; bx < base_size.width && ox < other_size.width; ++bx, ++ox) {
+               uint8_t* rp = rgba->data()[0] + ry * rgba->stride()[0];
+               for (int bx = start_base_x / bhf, ox = start_other_x / ohf; bx < base_size.width && ox < other_size.width; ++bx, ++ox) {
                        float const alpha = float (rp[3]) / 255;
                        *bp = *op * alpha + *bp * (1 - alpha);
                        ++bp;
                        ++op;
-                       rp += 4;
+                       rp += 4 * ohf;
                }
        }
 }
@@ -578,7 +589,7 @@ Image::alpha_blend (shared_ptr<const Image> other, Position<int> position)
        }
        case AV_PIX_FMT_YUV420P:
        {
-               shared_ptr<Image> yuv = other->scale (other->size(), dcp::YUV_TO_RGB_REC709, _pixel_format, false, false);
+               shared_ptr<Image> yuv = other->convert_pixel_format (dcp::YUV_TO_RGB_REC709, _pixel_format, false, false);
                component<uint8_t> (0, this, yuv, other, start_tx, start_ty, start_ox, start_oy);
                component<uint8_t> (1, this, yuv, other, start_tx, start_ty, start_ox, start_oy);
                component<uint8_t> (2, this, yuv, other, start_tx, start_ty, start_ox, start_oy);
@@ -587,7 +598,7 @@ Image::alpha_blend (shared_ptr<const Image> other, Position<int> position)
        case AV_PIX_FMT_YUV420P10:
        case AV_PIX_FMT_YUV422P10LE:
        {
-               shared_ptr<Image> yuv = other->scale (other->size(), dcp::YUV_TO_RGB_REC709, _pixel_format, false, false);
+               shared_ptr<Image> yuv = other->convert_pixel_format (dcp::YUV_TO_RGB_REC709, _pixel_format, false, false);
                component<uint16_t> (0, this, yuv, other, start_tx, start_ty, start_ox, start_oy);
                component<uint8_t>  (1, this, yuv, other, start_tx, start_ty, start_ox, start_oy);
                component<uint8_t>  (2, this, yuv, other, start_tx, start_ty, start_ox, start_oy);
@@ -1046,3 +1057,13 @@ Image::ensure_aligned (shared_ptr<Image> image)
 
        return shared_ptr<Image> (new Image (image, true));
 }
+
+size_t
+Image::memory_used () const
+{
+       size_t m = 0;
+       for (int i = 0; i < planes(); ++i) {
+               m += _stride[i] * sample_size(i).height;
+       }
+       return m;
+}