Rescale the image pixels using the full precision.

diff --git a/gui/apisurface.cpp b/gui/apisurface.cpp
index a872c13b6b2270a27eb68685a289b4827d77057c..22de5f0b0d873ab877c4c7dbd89fcdd7268e4fc6 100644 (file)
--- a/gui/apisurface.cpp
+++ b/gui/apisurface.cpp
@@ -128,8 +128,35 @@ ApiSurface::imageFromBase64(const QByteArray &base64)
 }
 
 
+static inline unsigned char clamp(int x)
+{
+    if (x <= 0) {
+        return 0;
+    }
+    if (x > 255) {
+        return 255;
+    }
+    return (unsigned char) x;
+}
+
+static inline unsigned char clamp(float x)
+{
+    if (x <= 0.0f) {
+        return 0;
+    }
+    if (x > 255.0f) {
+        return 255;
+    }
+    return (unsigned char) (x + 0.5f);
+}
+
+
 QImage
-ApiSurface::qimageFromRawImage(const image::Image *image)
+ApiSurface::qimageFromRawImage(const image::Image *image,
+                               float lowerValue,
+                               float upperValue,
+                               bool opaque,
+                               bool alpha)
 {
     QImage img;
     int width = image->width;
@@ -137,6 +164,14 @@ ApiSurface::qimageFromRawImage(const image::Image *image)
 
     img = QImage(width, height, QImage::Format_ARGB32);
 
+    int offset = - lowerValue * 255;
+    int scale = 256 / (upperValue - lowerValue);
+
+    float offset_f = - lowerValue;
+    float scale_f = 255.0f / (upperValue - lowerValue);
+
+    int aMask = (opaque || alpha) ? 0xff : 0;
+
     const unsigned char *srcRow = image->start();
     for (int y = 0; y < height; ++y) {
         QRgb *dst = (QRgb *)img.scanLine(y);
@@ -146,13 +181,17 @@ ApiSurface::qimageFromRawImage(const image::Image *image)
             for (int x = 0; x < width; ++x) {
                 unsigned char rgba[4] = {0, 0, 0, 0xff};
                 for (int c = 0; c < image->channels; ++c) {
-                    rgba[c] = *src++;
+                    rgba[c] = clamp(((*src++ + offset) * scale) >> 8);
                 }
                 if (image->channels == 1) {
                     // Use gray-scale instead of red
                     rgba[1] = rgba[0];
                     rgba[2] = rgba[0];
                 }
+                if (alpha) {
+                    rgba[2] = rgba[1] = rgba[0] = rgba[3];
+                }
+                rgba[3] |= aMask;
                 dst[x] = qRgba(rgba[0], rgba[1], rgba[2], rgba[3]);
             }
         } else {
@@ -160,22 +199,17 @@ ApiSurface::qimageFromRawImage(const image::Image *image)
             for (int x = 0; x < width; ++x) {
                 unsigned char rgba[4] = {0, 0, 0, 0xff};
                 for (int c = 0; c < image->channels; ++c) {
-                    float f = *src++;
-                    unsigned char u;
-                    if (f >= 1.0f) {
-                        u = 255;
-                    } else if (f <= 0.0f) {
-                        u = 0;
-                    } else {
-                        u = f * 255 + 0.5;
-                    }
-                    rgba[c] = u;
+                    rgba[c] = clamp((*src++ + offset_f)*scale_f);
                 }
                 if (image->channels == 1) {
                     // Use gray-scale instead of red
                     rgba[1] = rgba[0];
                     rgba[2] = rgba[0];
                 }
+                if (alpha) {
+                    rgba[2] = rgba[1] = rgba[0] = rgba[3];
+                }
+                rgba[3] |= aMask;
                 dst[x] = qRgba(rgba[0], rgba[1], rgba[2], rgba[3]);
             }
         }

diff --git a/gui/apisurface.h b/gui/apisurface.h
index 79afaf927ca5ccc9780b0de69dfb430d0e8814d4..ed6debe6ec2e662be64ddaee6d3098f961d0c6c8 100644 (file)
--- a/gui/apisurface.h
+++ b/gui/apisurface.h
@@ -29,7 +29,11 @@ public:
     QImage thumb() const;
 
     static image::Image *imageFromBase64(const QByteArray &data);
-    static QImage qimageFromRawImage(const image::Image *img);
+    static QImage qimageFromRawImage(const image::Image *img,
+                                     float lowerValue = 0.0f,
+                                     float upperValue = 1.0f,
+                                     bool opaque = false,
+                                     bool alpha = false);
 
 private:
     QSize  m_size;

diff --git a/gui/imageviewer.cpp b/gui/imageviewer.cpp
index a795993fb6c7b538128e477e3b625cbff9f0a4fc..eced83b63dd3eba1ae64fc36ced0c512e71b1a9d 100644 (file)
--- a/gui/imageviewer.cpp
+++ b/gui/imageviewer.cpp
@@ -70,17 +70,6 @@ void ImageViewer::setBase64Data(const QByteArray &base64)
     updateGeometry();
 }
 
-static inline int clamp(int x)
-{
-    if (x <= 0) {
-        return 0;
-    }
-    if (x > 255) {
-        return 255;
-    }
-    return x;
-}
-
 void ImageViewer::slotUpdate()
 {
     m_convertedImage =
@@ -92,51 +81,12 @@ void ImageViewer::slotUpdate()
     bool opaque = opaqueCheckBox->isChecked();
     bool alpha  = alphaCheckBox->isChecked();
 
-    if (lowerValue != 0.0 || upperValue != 1.0 || opaque || alpha) {
-        /*
-         * Rescale the image.
-         *
-         * XXX: This would be much more useful if done with the full precision
-         * of the original image
-         */
-
-        int offset = - lowerValue * 255;
-        int scale = 256 / (upperValue - lowerValue);
-
-        m_convertedImage =
-            m_convertedImage.convertToFormat(QImage::Format_ARGB32);
-
-        if (0) {
-            qDebug()
-                << "offset = " << offset << "\n"
-                << "scale = " << scale << "\n";
-        }
-
-        int width = m_convertedImage.width();
-        int height = m_convertedImage.height();
-
-        int aMask = opaque ? 0xff : 0;
-
-        for (int y = 0; y < height; ++y) {
-            QRgb *scanline = (QRgb *)m_convertedImage.scanLine(y);
-            for (int x = 0; x < width; ++x) {
-                QRgb pixel = scanline[x];
-                int r = qRed(pixel);
-                int g = qGreen(pixel);
-                int b = qBlue(pixel);
-                int a = qAlpha(pixel);
-                if (alpha) {
-                    a = clamp(((a + offset) * scale) >> 8);
-                    scanline[x] = qRgba(a, a, a, 0xff);
-                } else {
-                    r = clamp(((r + offset) * scale) >> 8);
-                    g = clamp(((g + offset) * scale) >> 8);
-                    b = clamp(((b + offset) * scale) >> 8);
-                    a |= aMask;
-                    scanline[x] = qRgba(r, g, b, a);
-                }
-            }
-        }
+    m_convertedImage = ApiSurface::qimageFromRawImage(m_image,
+                                                      lowerValue, upperValue,
+                                                      opaque, alpha);
+
+    if (flipCheckBox->isChecked()) {
+        m_convertedImage = m_convertedImage.mirrored(false, true);
     }
 
     m_pixelWidget->setSurface(m_convertedImage);