Speed up blurhash code

src/BlurhashProvider.cpp

@@ -17,26 +17,13 @@ BlurhashProvider::requestImage(const QString &id, QSize *size, const QSize &requ
                 *size = sz;
 
         auto decoded = blurhash::decode(
-          QUrl::fromPercentEncoding(id.toUtf8()).toStdString(), sz.width(), sz.height());
+          QUrl::fromPercentEncoding(id.toUtf8()).toStdString(), sz.width(), sz.height(), 4);
         if (decoded.image.empty()) {
                 *size = QSize();
                 return QImage();
         }
 
-        QImage image(sz, QImage::Format_RGB888);
+        QImage image(decoded.image.data(), decoded.width, decoded.height, QImage::Format_RGB32);
 
-        for (int y = 0; y < sz.height(); y++) {
-                for (int x = 0; x < sz.width(); x++) {
-                        int base = (y * sz.width() + x) * 3;
-                        image.setPixel(x,
-                                       y,
-                                       qRgb(decoded.image[base],
-                                            decoded.image[base + 1],
-                                            decoded.image[base + 2]));
-                }
-        }
-
-        // std::copy(decoded.image.begin(), decoded.image.end(), image.bits());
-
-        return image;
+        return image.copy();
 }

src/ChatPage.cpp

@@ -332,6 +332,8 @@ ChatPage::ChatPage(QSharedPointer<UserSettings> userSettings, QWidget *parent)
 
                           QImage img;
                           img.loadFromData(bin);
+                          if (img.height() > 200 && img.width() > 360)
+                                  img = img.scaled(360, 200, Qt::KeepAspectRatioByExpanding);
                           std::vector<unsigned char> data;
                           for (int y = 0; y < img.height(); y++) {
                                   for (int x = 0; x < img.width(); x++) {

third_party/blurhash/blurhash.cpp

@@ -251,7 +251,7 @@ multiplyBasisFunction(Components components, int width, int height, unsigned cha
 
 namespace blurhash {
 Image
-decode(std::string_view blurhash, size_t width, size_t height)
+decode(std::string_view blurhash, size_t width, size_t height, size_t bytesPerPixel)
 {
         Image i{};
 
@@ -295,6 +295,9 @@ decode(std::string_view blurhash, size_t width, size_t height)
                         i.image.push_back(static_cast<unsigned char>(linearToSrgb(c.r)));
                         i.image.push_back(static_cast<unsigned char>(linearToSrgb(c.g)));
                         i.image.push_back(static_cast<unsigned char>(linearToSrgb(c.b)));
+
+                        for (size_t p = 3; p < bytesPerPixel; p++)
+                                i.image.push_back(255);
                 }
         }
 

third_party/blurhash/blurhash.hpp

@@ -13,7 +13,7 @@ struct Image
 
 // Decode a blurhash to an image with size width*height
 Image
-decode(std::string_view blurhash, size_t width, size_t height);
+decode(std::string_view blurhash, size_t width, size_t height, size_t bytesPerPixel = 3);
 
 // Encode an image of rgb pixels (without padding) with size width*height into a blurhash with x*y
 // components