};
// Constants for wxImage::Scale() for determining the level of quality
-enum
+enum wxImageResizeQuality
{
- wxIMAGE_QUALITY_NORMAL = 0,
- wxIMAGE_QUALITY_HIGH = 1
+ // different image resizing algorithms used by Scale() and Rescale()
+ wxIMAGE_QUALITY_NEAREST = 0,
+ wxIMAGE_QUALITY_BILINEAR = 1,
+ wxIMAGE_QUALITY_BICUBIC = 2,
+
+ // default quality is low (but fast)
+ wxIMAGE_QUALITY_NORMAL = wxIMAGE_QUALITY_NEAREST,
+
+ // highest (but best) quality
+ wxIMAGE_QUALITY_HIGH = wxIMAGE_QUALITY_BICUBIC
};
// alpha channel values: fully transparent, default threshold separating
void Paste( const wxImage &image, int x, int y );
// return the new image with size width*height
- wxImage Scale( int width, int height, int quality = wxIMAGE_QUALITY_NORMAL ) const;
+ wxImage Scale( int width, int height,
+ wxImageResizeQuality quality = wxIMAGE_QUALITY_NORMAL ) const;
// box averager and bicubic filters for up/down sampling
+ wxImage ResampleNearest(int width, int height) const;
wxImage ResampleBox(int width, int height) const;
+ wxImage ResampleBilinear(int width, int height) const;
wxImage ResampleBicubic(int width, int height) const;
// blur the image according to the specified pixel radius
wxImage ShrinkBy( int xFactor , int yFactor ) const ;
// rescales the image in place
- wxImage& Rescale( int width, int height, int quality = wxIMAGE_QUALITY_NORMAL ) { return *this = Scale(width, height, quality); }
+ wxImage& Rescale( int width, int height,
+ wxImageResizeQuality quality = wxIMAGE_QUALITY_NORMAL )
+ { return *this = Scale(width, height, quality); }
// resizes the image in place
wxImage& Resize( const wxSize& size, const wxPoint& pos,
wxIMAGE_RESOLUTION_CM = 2
};
+/**
+ Image resize algorithm.
+
+ This is used with wxImage::Scale() and wxImage::Rescale().
+ */
+enum wxImageResizeQuality
+{
+ /// Simplest and fastest algorithm.
+ wxIMAGE_QUALITY_NEAREST,
+
+ /// Compromise between wxIMAGE_QUALITY_NEAREST and wxIMAGE_QUALITY_BICUBIC.
+ wxIMAGE_QUALITY_BILINEAR,
+
+ /// Highest quality but slowest execution time.
+ wxIMAGE_QUALITY_BICUBIC,
+
+ /// Default image resizing algorithm used by wxImage::Scale().
+ wxIMAGE_QUALITY_NORMAL,
+
+ /// Best image resizing algorithm, currently same as wxIMAGE_QUALITY_BICUBIC.
+ wxIMAGE_QUALITY_HIGH
+};
+
/**
Possible values for PNG image type option.
@see Scale()
*/
wxImage& Rescale(int width, int height,
- int quality = wxIMAGE_QUALITY_NORMAL);
+ wxImageResizeQuality quality = wxIMAGE_QUALITY_NORMAL);
/**
Changes the size of the image in-place without scaling it by adding either a
This is also useful for scaling bitmaps in general as the only other way
to scale bitmaps is to blit a wxMemoryDC into another wxMemoryDC.
- The parameter @a quality determines what method to use for resampling the image.
- Can be one of the following:
- - wxIMAGE_QUALITY_NORMAL: Uses the normal default scaling method of pixel
- replication
- - wxIMAGE_QUALITY_HIGH: Uses bicubic and box averaging resampling methods
- for upsampling and downsampling respectively
+ The parameter @a quality determines what method to use for resampling
+ the image, see wxImageResizeQuality documentation.
It should be noted that although using @c wxIMAGE_QUALITY_HIGH produces much nicer
looking results it is a slower method. Downsampling will use the box averaging
@see Rescale()
*/
wxImage Scale(int width, int height,
- int quality = wxIMAGE_QUALITY_NORMAL) const;
+ wxImageResizeQuality quality = wxIMAGE_QUALITY_NORMAL) const;
/**
Returns a resized version of this image without scaling it by adding either a
return image;
}
-wxImage wxImage::Scale( int width, int height, int quality ) const
+wxImage
+wxImage::Scale( int width, int height, wxImageResizeQuality quality ) const
{
wxImage image;
if ( old_width == width && old_height == height )
return *this;
- // Scale the image (...or more appropriately, resample the image) using
- // either the high-quality or normal method as specified
- if ( quality == wxIMAGE_QUALITY_HIGH )
- {
- // We need to check whether we are downsampling or upsampling the image
- if ( width < old_width && height < old_height )
- {
- // Downsample the image using the box averaging method for best results
- image = ResampleBox(width, height);
- }
- else
- {
- // For upsampling or other random/wierd image dimensions we'll use
- // a bicubic b-spline scaling method
- image = ResampleBicubic(width, height);
- }
- }
- else // Default scaling method == simple pixel replication
- {
- if ( old_width % width == 0 && old_width >= width &&
- old_height % height == 0 && old_height >= height )
- {
- return ShrinkBy( old_width / width , old_height / height ) ;
- }
- image.Create( width, height, false );
-
- unsigned char *data = image.GetData();
-
- wxCHECK_MSG( data, image, wxT("unable to create image") );
-
- unsigned char *source_data = M_IMGDATA->m_data;
- unsigned char *target_data = data;
- unsigned char *source_alpha = 0 ;
- unsigned char *target_alpha = 0 ;
-
- if ( !M_IMGDATA->m_hasMask )
- {
- source_alpha = M_IMGDATA->m_alpha ;
- if ( source_alpha )
- {
- image.SetAlpha() ;
- target_alpha = image.GetAlpha() ;
- }
- }
-
- long x_delta = (old_width<<16) / width;
- long y_delta = (old_height<<16) / height;
-
- unsigned char* dest_pixel = target_data;
-
- long y = 0;
- for ( long j = 0; j < height; j++ )
- {
- unsigned char* src_line = &source_data[(y>>16)*old_width*3];
- unsigned char* src_alpha_line = source_alpha ? &source_alpha[(y>>16)*old_width] : 0 ;
-
- long x = 0;
- for ( long i = 0; i < width; i++ )
+ // resample the image using either the nearest neighbourhood, bilinear or
+ // bicubic method as specified
+ switch ( quality )
+ {
+ case wxIMAGE_QUALITY_BICUBIC:
+ case wxIMAGE_QUALITY_BILINEAR:
+ // both of these algorithms should be used for up-sampling the
+ // image only, when down-sampling always use box averaging for best
+ // results
+ if ( width < old_width && height < old_height )
+ image = ResampleBox(width, height);
+ else if ( quality == wxIMAGE_QUALITY_BILINEAR )
+ image = ResampleBilinear(width, height);
+ else if ( quality == wxIMAGE_QUALITY_BICUBIC )
+ image = ResampleBicubic(width, height);
+ break;
+
+ case wxIMAGE_QUALITY_NEAREST:
+ if ( old_width % width == 0 && old_width >= width &&
+ old_height % height == 0 && old_height >= height )
{
- unsigned char* src_pixel = &src_line[(x>>16)*3];
- unsigned char* src_alpha_pixel = source_alpha ? &src_alpha_line[(x>>16)] : 0 ;
- dest_pixel[0] = src_pixel[0];
- dest_pixel[1] = src_pixel[1];
- dest_pixel[2] = src_pixel[2];
- dest_pixel += 3;
- if ( source_alpha )
- *(target_alpha++) = *src_alpha_pixel ;
- x += x_delta;
+ return ShrinkBy( old_width / width , old_height / height );
}
- y += y_delta;
- }
+ image = ResampleNearest(width, height);
+ break;
}
// If the original image has a mask, apply the mask to the new image
return image;
}
+wxImage wxImage::ResampleNearest(int width, int height) const
+{
+ wxImage image;
+ image.Create( width, height, false );
+
+ unsigned char *data = image.GetData();
+
+ wxCHECK_MSG( data, image, wxT("unable to create image") );
+
+ unsigned char *source_data = M_IMGDATA->m_data;
+ unsigned char *target_data = data;
+ unsigned char *source_alpha = 0 ;
+ unsigned char *target_alpha = 0 ;
+
+ if ( !M_IMGDATA->m_hasMask )
+ {
+ source_alpha = M_IMGDATA->m_alpha ;
+ if ( source_alpha )
+ {
+ image.SetAlpha() ;
+ target_alpha = image.GetAlpha() ;
+ }
+ }
+
+ long old_height = M_IMGDATA->m_height,
+ old_width = M_IMGDATA->m_width;
+ long x_delta = (old_width<<16) / width;
+ long y_delta = (old_height<<16) / height;
+
+ unsigned char* dest_pixel = target_data;
+
+ long y = 0;
+ for ( long j = 0; j < height; j++ )
+ {
+ unsigned char* src_line = &source_data[(y>>16)*old_width*3];
+ unsigned char* src_alpha_line = source_alpha ? &source_alpha[(y>>16)*old_width] : 0 ;
+
+ long x = 0;
+ for ( long i = 0; i < width; i++ )
+ {
+ unsigned char* src_pixel = &src_line[(x>>16)*3];
+ unsigned char* src_alpha_pixel = source_alpha ? &src_alpha_line[(x>>16)] : 0 ;
+ dest_pixel[0] = src_pixel[0];
+ dest_pixel[1] = src_pixel[1];
+ dest_pixel[2] = src_pixel[2];
+ dest_pixel += 3;
+ if ( source_alpha )
+ *(target_alpha++) = *src_alpha_pixel ;
+ x += x_delta;
+ }
+
+ y += y_delta;
+ }
+
+ return image;
+}
+
wxImage wxImage::ResampleBox(int width, int height) const
{
// This function implements a simple pre-blur/box averaging method for
return ret_image;
}
+wxImage wxImage::ResampleBilinear(int width, int height) const
+{
+ // This function implements a Bilinear algorithm for resampling.
+ wxImage ret_image(width, height, false);
+ unsigned char* src_data = M_IMGDATA->m_data;
+ unsigned char* src_alpha = M_IMGDATA->m_alpha;
+ unsigned char* dst_data = ret_image.GetData();
+ unsigned char* dst_alpha = NULL;
+
+ if ( src_alpha )
+ {
+ ret_image.SetAlpha();
+ dst_alpha = ret_image.GetAlpha();
+ }
+ double HFactor = double(M_IMGDATA->m_height) / height;
+ double WFactor = double(M_IMGDATA->m_width) / width;
+
+ int srcpixymax = M_IMGDATA->m_height - 1;
+ int srcpixxmax = M_IMGDATA->m_width - 1;
+
+ double srcpixy, srcpixy1, srcpixy2, dy, dy1;
+ double srcpixx, srcpixx1, srcpixx2, dx, dx1;
+ double r1, g1, b1, a1;
+ double r2, g2, b2, a2;
+
+ for ( int dsty = 0; dsty < height; dsty++ )
+ {
+ // We need to calculate the source pixel to interpolate from - Y-axis
+ srcpixy = double(dsty) * HFactor;
+ srcpixy1 = int(srcpixy);
+ srcpixy2 = ( srcpixy1 == srcpixymax ) ? srcpixy1 : srcpixy1 + 1.0;
+ dy = srcpixy - (int)srcpixy;
+ dy1 = 1.0 - dy;
+
+
+ for ( int dstx = 0; dstx < width; dstx++ )
+ {
+ // X-axis of pixel to interpolate from
+ srcpixx = double(dstx) * WFactor;
+ srcpixx1 = int(srcpixx);
+ srcpixx2 = ( srcpixx1 == srcpixxmax ) ? srcpixx1 : srcpixx1 + 1.0;
+ dx = srcpixx - (int)srcpixx;
+ dx1 = 1.0 - dx;
+
+ int x_offset1 = srcpixx1 < 0.0 ? 0 : srcpixx1 > srcpixxmax ? srcpixxmax : (int)srcpixx1;
+ int x_offset2 = srcpixx2 < 0.0 ? 0 : srcpixx2 > srcpixxmax ? srcpixxmax : (int)srcpixx2;
+ int y_offset1 = srcpixy1 < 0.0 ? 0 : srcpixy1 > srcpixymax ? srcpixymax : (int)srcpixy1;
+ int y_offset2 = srcpixy2 < 0.0 ? 0 : srcpixy2 > srcpixymax ? srcpixymax : (int)srcpixy2;
+
+ int src_pixel_index00 = y_offset1 * M_IMGDATA->m_width + x_offset1;
+ int src_pixel_index01 = y_offset1 * M_IMGDATA->m_width + x_offset2;
+ int src_pixel_index10 = y_offset2 * M_IMGDATA->m_width + x_offset1;
+ int src_pixel_index11 = y_offset2 * M_IMGDATA->m_width + x_offset2;
+
+ //first line
+ r1 = src_data[src_pixel_index00 * 3 + 0] * dx1 + src_data[src_pixel_index01 * 3 + 0] * dx;
+ g1 = src_data[src_pixel_index00 * 3 + 1] * dx1 + src_data[src_pixel_index01 * 3 + 1] * dx;
+ b1 = src_data[src_pixel_index00 * 3 + 2] * dx1 + src_data[src_pixel_index01 * 3 + 2] * dx;
+ if ( src_alpha )
+ a1 = src_alpha[src_pixel_index00] * dx1 + src_alpha[src_pixel_index01] * dx;
+
+ //second line
+ r2 = src_data[src_pixel_index10 * 3 + 0] * dx1 + src_data[src_pixel_index11 * 3 + 0] * dx;
+ g2 = src_data[src_pixel_index10 * 3 + 1] * dx1 + src_data[src_pixel_index11 * 3 + 1] * dx;
+ b2 = src_data[src_pixel_index10 * 3 + 2] * dx1 + src_data[src_pixel_index11 * 3 + 2] * dx;
+ if ( src_alpha )
+ a2 = src_alpha[src_pixel_index10] * dx1 + src_alpha[src_pixel_index11] * dx;
+
+ //result lines
+
+ dst_data[0] = r1 * dy1 + r2 * dy;
+ dst_data[1] = g1 * dy1 + g2 * dy;
+ dst_data[2] = b1 * dy1 + b2 * dy;
+ dst_data += 3;
+
+ if ( src_alpha )
+ *dst_alpha++ = a1 * dy1 + a2 * dy;
+ }
+ }
+
+ return ret_image;
+}
+
// The following two local functions are for the B-spline weighting of the
// bicubic sampling algorithm
static inline double spline_cube(double value)
projects / wxWidgets.git / commitdiff
