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Fixed issues with Wipe transition destroying the existing alpha channel. It now adds the alpha channels together, to maintain the original... but it is very slow. I'm still looking to optimize it.

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This commit is contained in:
Jonathan Thomas
2013-10-11 15:54:56 -05:00
parent 092123de87
commit 3617d6be31
2 changed files with 39 additions and 12 deletions
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2
include/effects/Wipe.h
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@@ -59,8 +59,6 @@ namespace openshot
Keyframe brightness;
Keyframe contrast;
tr1::shared_ptr<Magick::Image> mask;
tr1::shared_ptr<Magick::Image> white;
tr1::shared_ptr<Magick::Image> black;
/// Set brightness and contrast
void set_brightness_and_contrast(tr1::shared_ptr<Magick::Image> image, float brightness, float contrast);

49
src/effects/Wipe.cpp
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@@ -69,6 +69,8 @@ void Wipe::set_brightness_and_contrast(tr1::shared_ptr<Magick::Image> image, flo
{
// Make mask darker
double black_alpha = abs(brightness) / 100.0;
tr1::shared_ptr<Magick::Image> black = tr1::shared_ptr<Magick::Image>(new Magick::Image(mask->size(), Magick::Color("Black")));
black->matte(true);
black->quantumOperator(Magick::OpacityChannel, Magick::MultiplyEvaluateOperator, black_alpha);
image->composite(*black.get(), 0, 0, Magick::OverCompositeOp);
@@ -77,6 +79,8 @@ void Wipe::set_brightness_and_contrast(tr1::shared_ptr<Magick::Image> image, flo
{
// Make mask whiter
double white_alpha = brightness / 100.0;
tr1::shared_ptr<Magick::Image> white = tr1::shared_ptr<Magick::Image>(new Magick::Image(mask->size(), Magick::Color("White")));
white->matte(true);
white->quantumOperator(Magick::OpacityChannel, Magick::MultiplyEvaluateOperator, white_alpha);
image->composite(*white.get(), 0, 0, Magick::OverCompositeOp);
}
@@ -98,15 +102,6 @@ tr1::shared_ptr<Frame> Wipe::GetFrame(tr1::shared_ptr<Frame> frame, int frame_nu
mask->resize(new_size);
}
// Load white & black images, to quickly lighten and darken the mask (for animation)
white = tr1::shared_ptr<Magick::Image>(new Magick::Image(mask->size(), Magick::Color("White")));
black = tr1::shared_ptr<Magick::Image>(new Magick::Image(mask->size(), Magick::Color("Black")));
// Give white & black images a transparent background color
white->matte(true);
black->matte(true);
// Make a copy of the resized image (since we will be modifying the brightness and contrast)
tr1::shared_ptr<Magick::Image> image = tr1::shared_ptr<Magick::Image>(new Magick::Image(*mask.get()));
@@ -114,7 +109,41 @@ tr1::shared_ptr<Frame> Wipe::GetFrame(tr1::shared_ptr<Frame> frame, int frame_nu
set_brightness_and_contrast(image, brightness.GetValue(frame_number), contrast.GetValue(frame_number));
// Composite the alpha channel of our mask onto our frame's alpha channel
frame->GetImage()->composite(*image.get(), 0, 0, Magick::CopyOpacityCompositeOp);
tr1::shared_ptr<Magick::Image> alpha_image = tr1::shared_ptr<Magick::Image>(new Magick::Image(mask->size(), Magick::Color("White")));
alpha_image->backgroundColor(Magick::Color("none"));
alpha_image->matte(true);
alpha_image->composite(*image.get(), 0, 0, Magick::CopyOpacityCompositeOp);
// Add 2 alpha channels together (i.e. maintain the original alpha while adding more)
// Prepare to update image
frame->GetImage()->modifyImage();
// Loop through each row
for (int row = 0; row < frame->GetImage()->size().height(); row++)
{
const Magick::PixelPacket* original_pixels = frame->GetImage()->getConstPixels(0, row, frame->GetImage()->columns(), 1);
const Magick::PixelPacket* alpha_pixels = alpha_image->getConstPixels(0, row, alpha_image->columns(), 1);
// Loop through each column
for (int col = 0; col < frame->GetImage()->size().width(); col++)
{
// Calculate new opacity value (and prevent overflow)
int new_alpha = original_pixels[col].opacity + alpha_pixels[col].opacity;
if (new_alpha > 65535.0)
new_alpha = 65535.0;
// Set the new opacity
frame->GetImage()->pixelColor(col, row, Magick::Color(original_pixels[col].red, original_pixels[col].green, original_pixels[col].blue, new_alpha));
}
}
// Transfer image cache pixels to the image
frame->GetImage()->syncPixels();
// Copy the combined alpha channel back to the frame
//frame->GetImage()->composite(*combined_image.get(), 0, 0, Magick::CopyOpacityCompositeOp);
// return the modified frame
return frame;