+
+
+//-----------------------------------------------------------------------------
+
+// GRG, Dic/99
+// Counts and returns the number of different colours. Optionally stops
+// when it exceeds 'stopafter' different colours. This is useful, for
+// example, to see if the image can be saved as 8-bit (256 colour or
+// less, in this case it would be invoked as CountColours(256)). Default
+// value for stopafter is -1 (don't care).
+//
+unsigned long wxImage::CountColours( unsigned long stopafter )
+{
+ wxHashTable h;
+ wxNode *node;
+ wxHNode *hnode;
+ unsigned char r, g, b, *p;
+ unsigned long size, nentries, key;
+
+ p = GetData();
+ size = GetWidth() * GetHeight();
+ nentries = 0;
+
+ for (unsigned long j = 0; (j < size) && (nentries <= stopafter) ; j++)
+ {
+ r = *(p++);
+ g = *(p++);
+ b = *(p++);
+ key = (r << 16) | (g << 8) | b;
+
+ hnode = (wxHNode *) h.Get(key);
+
+ if (!hnode)
+ {
+ h.Put(key, (wxObject *)(new wxHNode));
+ nentries++;
+ }
+ }
+
+ // delete all HNodes
+ h.BeginFind();
+ while ((node = h.Next()) != NULL)
+ delete (wxHNode *)node->GetData();
+
+ return nentries;
+}
+
+
+// GRG, Dic/99
+// Computes the histogram of the image and fills a hash table, indexed
+// with integer keys built as 0xRRGGBB, containing wxHNode objects. Each
+// wxHNode contains an 'index' (useful to build a palette with the image
+// colours) and a 'value', which is the number of pixels in the image with
+// that colour.
+//
+unsigned long wxImage::ComputeHistogram( wxHashTable &h )
+{
+ unsigned char r, g, b, *p;
+ unsigned long size, nentries, key;
+ wxHNode *hnode;
+
+ p = GetData();
+ size = GetWidth() * GetHeight();
+ nentries = 0;
+
+ for (unsigned long j = 0; j < size; j++)
+ {
+ r = *(p++);
+ g = *(p++);
+ b = *(p++);
+ key = (r << 16) | (g << 8) | b;
+
+ hnode = (wxHNode *) h.Get(key);
+
+ if (hnode)
+ hnode->value++;
+ else
+ {
+ hnode = new wxHNode();
+ hnode->index = nentries++;
+ hnode->value = 1;
+
+ h.Put(key, (wxObject *)hnode);
+ }
+ }
+
+ return nentries;
+}
+
+/*
+ * Rotation code by Carlos Moreno
+ */
+
+struct wxRotationPixel
+{
+ unsigned char rgb[3];
+};
+
+struct wxRotationPoint
+{
+ wxRotationPoint (double _x, double _y) : x(_x), y(_y) {}
+ wxRotationPoint (const wxPoint & p) : x(p.x), y(p.y) {}
+ double x, y;
+};
+
+static const wxRotationPixel gs_BlankPixel = {0,0,0};
+static const double gs_Epsilon = 1e-10;
+
+static inline int wxCint (double x)
+{
+ return (x > 0) ? (int) (x + 0.5) : (int) (x - 0.5);
+}
+
+
+// Auxiliary function to rotate a point (x,y) with respect to point p0
+// make it inline and use a straight return to facilitate optimization
+// also, the function receives the sine and cosine of the angle to avoid
+// repeating the time-consuming calls to these functions -- sin/cos can
+// be computed and stored in the calling function.
+
+inline wxRotationPoint rotated_point (const wxRotationPoint & p, double cos_angle, double sin_angle, const wxRotationPoint & p0)
+{
+ return wxRotationPoint (p0.x + (p.x - p0.x) * cos_angle - (p.y - p0.y) * sin_angle,
+ p0.y + (p.y - p0.y) * cos_angle + (p.x - p0.x) * sin_angle);
+}
+
+inline wxRotationPoint rotated_point (double x, double y, double cos_angle, double sin_angle, const wxRotationPoint & p0)
+{
+ return rotated_point (wxRotationPoint(x,y), cos_angle, sin_angle, p0);
+}
+
+wxImage wxImage::Rotate(double angle, const wxPoint & centre_of_rotation, bool interpolating, wxPoint * offset_after_rotation) const
+{
+ const wxImage& img = * this;
+ int i;
+ angle = -angle; // screen coordinates are a mirror image of "real" coordinates
+
+ // Create pointer-based array to accelerate access to wxImage's data
+ wxRotationPixel ** data = new wxRotationPixel * [img.GetHeight()];
+
+ data[0] = (wxRotationPixel *) img.GetData();
+
+ for (i = 1; i < img.GetHeight(); i++)
+ {
+ data[i] = data[i - 1] + img.GetWidth();
+ }
+
+ // pre-compute coefficients for rotation formula (sine and cosine of the angle)
+ const double cos_angle = cos(angle);
+ const double sin_angle = sin(angle);
+
+ // Create new Image to store the result
+ // First, find rectangle that covers the rotated image; to do that,
+ // rotate the four corners
+
+ const wxRotationPoint p0 = centre_of_rotation;
+
+ wxRotationPoint p1 = rotated_point (0, 0, cos_angle, sin_angle, p0);
+ wxRotationPoint p2 = rotated_point (0, img.GetHeight(), cos_angle, sin_angle, p0);
+ wxRotationPoint p3 = rotated_point (img.GetWidth(), 0, cos_angle, sin_angle, p0);
+ wxRotationPoint p4 = rotated_point (img.GetWidth(), img.GetHeight(), cos_angle, sin_angle, p0);
+
+ int x1 = (int) floor (wxMin (wxMin(p1.x, p2.x), wxMin(p3.x, p4.x)));
+ int y1 = (int) floor (wxMin (wxMin(p1.y, p2.y), wxMin(p3.y, p4.y)));
+
+ int x2 = (int) ceil (wxMax (wxMax(p1.x, p2.x), wxMax(p3.x, p4.x)));
+ int y2 = (int) ceil (wxMax (wxMax(p1.y, p2.y), wxMax(p3.y, p4.y)));
+
+ wxImage rotated (x2 - x1 + 1, y2 - y1 + 1);
+
+ if (offset_after_rotation != NULL)
+ {
+ *offset_after_rotation = wxPoint (x1, y1);
+ }
+
+
+ wxRotationPixel ** result_data = new wxRotationPixel * [rotated.GetHeight()];
+
+ result_data[0] = (wxRotationPixel *) rotated.GetData();
+
+ for (i = 1; i < rotated.GetHeight(); i++)
+ {
+ result_data[i] = result_data[i - 1] + rotated.GetWidth();
+ }
+
+ // Now, for each point of the rotated image, find where it came from, by
+ // performing an inverse rotation (a rotation of -angle) and getting the
+ // pixel at those coordinates
+
+ int x;
+ for (x = 0; x < rotated.GetWidth(); x++)
+ {
+ for (int y = 0; y < rotated.GetHeight(); y++)
+ {
+ wxRotationPoint src = rotated_point (x + x1, y + y1, cos_angle, -sin_angle, p0);
+
+ if (interpolating)
+ {
+ if (0 < src.x && src.x < img.GetWidth() - 1 &&
+ 0 < src.y && src.y < img.GetHeight() - 1)
+ {
+ // interpolate using the 4 enclosing grid-points. Those
+ // points can be obtained using floor and ceiling of the
+ // exact coordinates of the point
+
+ const int x1 = wxCint(floor(src.x));
+ const int y1 = wxCint(floor(src.y));
+ const int x2 = wxCint(ceil(src.x));
+ const int y2 = wxCint(ceil(src.y));
+
+ // get four points and the distances (square of the distance,
+ // for efficiency reasons) for the interpolation formula
+ const wxRotationPixel & v1 = data[y1][x1];
+ const wxRotationPixel & v2 = data[y1][x2];
+ const wxRotationPixel & v3 = data[y2][x2];
+ const wxRotationPixel & v4 = data[y2][x1];
+
+ const double d1 = (src.x - x1) * (src.x - x1) + (src.y - y1) * (src.y - y1);
+ const double d2 = (src.x - x2) * (src.x - x2) + (src.y - y1) * (src.y - y1);
+ const double d3 = (src.x - x2) * (src.x - x2) + (src.y - y2) * (src.y - y2);
+ const double d4 = (src.x - x1) * (src.x - x1) + (src.y - y2) * (src.y - y2);
+
+ // Now interpolate as a weighted average of the four surrounding
+ // points, where the weights are the distances to each of those points
+
+ // If the point is exactly at one point of the grid of the source
+ // image, then don't interpolate -- just assign the pixel
+
+ if (d1 < gs_Epsilon) // d1,d2,d3,d4 are positive -- no need for abs()
+ {
+ result_data[y][x] = v1;
+ }
+ else if (d2 < gs_Epsilon)
+ {
+ result_data[y][x] = v2;
+ }
+ else if (d3 < gs_Epsilon)
+ {
+ result_data[y][x] = v3;
+ }
+ else if (d4 < gs_Epsilon)
+ {
+ result_data[y][x] = v4;
+ }
+ else
+ {
+ // weights for the weighted average are proportional to the inverse of the distance
+ const double w1 = 1/d1, w2 = 1/d2, w3 = 1/d3, w4 = 1/d4;
+
+ for (int i = 0; i < 3; i++) // repeat calculation for R, G, and B
+ {
+ result_data[y][x].rgb[i] =
+ (unsigned char) ( (w1 * v1.rgb[i] + w2 * v2.rgb[i] +
+ w3 * v3.rgb[i] + w4 * v4.rgb[i]) /
+ (w1 + w2 + w3 + w4) );
+ }
+ }
+ }
+ else
+ {
+ result_data[y][x] = gs_BlankPixel;
+ }
+ }
+ else
+ {
+ const int xs = wxCint (src.x); // wxCint performs rounding to the
+ const int ys = wxCint (src.y); // closest integer
+
+ if (0 <= xs && xs < img.GetWidth() &&
+ 0 <= ys && ys < img.GetHeight())
+ {
+ result_data[y][x] = data[ys][xs];
+ }
+ else
+ {
+ result_data[y][x] = gs_BlankPixel;
+ }
+ }
+ }
+ }
+
+ return rotated;
+}
+
projects / wxWidgets.git / blobdiff