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speed up Rescale 5- to 15-fold by using pixbuf scaling

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@46057 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Paul Cornett
2007-05-16 02:45:01 +00:00
parent 155c2f6c82
commit 533b005afd
1 changed files with 45 additions and 157 deletions
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202
src/gtk/bitmap.cpp
View File

@@ -304,7 +304,7 @@ wxBitmap wxBitmap::Rescale(int clipx, int clipy, int clipwidth, int clipheight,
wxCHECK_MSG(Ok(), bmp, wxT("invalid bitmap"));
if (newy==M_BMPDATA->m_width && newy==M_BMPDATA->m_height)
if (newx==M_BMPDATA->m_width && newy==M_BMPDATA->m_height)
return *this;
int width = wxMax(newx, 1);
@@ -312,169 +312,57 @@ wxBitmap wxBitmap::Rescale(int clipx, int clipy, int clipwidth, int clipheight,
width = wxMin(width, clipwidth);
height = wxMin(height, clipheight);
// scale pixbuf if available and it has alpha or there is no mask
if (M_BMPDATA->m_pixbuf != NULL && (
M_BMPDATA->m_mask == NULL || gdk_pixbuf_get_has_alpha(M_BMPDATA->m_pixbuf)))
{
bmp.SetPixbuf(gdk_pixbuf_new(GDK_COLORSPACE_RGB,
gdk_pixbuf_get_has_alpha(M_BMPDATA->m_pixbuf),
8, width, height), M_BMPDATA->m_bpp);
gdk_pixbuf_scale(M_BMPDATA->m_pixbuf, bmp.GetPixbuf(),
0, 0, width, height,
clipx, clipy,
(double)newx/GetWidth(), (double)newy/GetHeight(),
GDK_INTERP_BILINEAR);
}
const double scale_x = double(newx) / M_BMPDATA->m_width;
const double scale_y = double(newy) / M_BMPDATA->m_height;
// Converting to pixbuf, scaling with gdk_pixbuf_scale, and converting
// back, is faster than scaling pixmap ourselves.
// use pixbuf if already available,
// otherwise create temporary pixbuf from pixmap
GdkPixbuf* pixbuf = M_BMPDATA->m_pixbuf;
if (pixbuf)
g_object_ref(pixbuf);
else
pixbuf = gdk_pixbuf_get_from_drawable(
NULL, M_BMPDATA->m_pixmap, NULL,
0, 0, 0, 0, M_BMPDATA->m_width, M_BMPDATA->m_height);
// new pixbuf for scaled wxBitmap
GdkPixbuf* pixbuf_scaled = gdk_pixbuf_new(
GDK_COLORSPACE_RGB, gdk_pixbuf_get_has_alpha(pixbuf), 8, width, height);
// GDK_INTERP_NEAREST is the lowest-quality method for continuous-tone
// images, but the only one which preserves sharp edges
gdk_pixbuf_scale(
pixbuf, pixbuf_scaled,
0, 0, width, height, clipx, clipy, scale_x, scale_y,
GDK_INTERP_NEAREST);
g_object_unref(pixbuf);
bmp.SetPixbuf(pixbuf_scaled, M_BMPDATA->m_bpp);
if (M_BMPDATA->m_mask)
{
GdkImage* img = gdk_drawable_get_image(
M_BMPDATA->m_pixmap, 0, 0, M_BMPDATA->m_width, M_BMPDATA->m_height);
pixbuf = gdk_pixbuf_get_from_drawable(
NULL, M_BMPDATA->m_mask->m_bitmap, NULL,
0, 0, 0, 0, M_BMPDATA->m_width, M_BMPDATA->m_height);
wxCHECK_MSG(img, bmp, wxT("couldn't create image"));
pixbuf_scaled = gdk_pixbuf_new(
GDK_COLORSPACE_RGB, false, 8, width, height);
GdkGC *gc = NULL;
GdkPixmap *dstpix = NULL;
char *dst = NULL;
long dstbyteperline = 0;
gdk_pixbuf_scale(
pixbuf, pixbuf_scaled,
0, 0, width, height, clipx, clipy, scale_x, scale_y,
GDK_INTERP_NEAREST);
if (GetDepth() != 1)
{
bmp.Create(width, height, gdk_drawable_get_depth(M_BMPDATA->m_pixmap));
dstpix = bmp.GetPixmap();
gc = gdk_gc_new( dstpix );
}
else
{
dstbyteperline = (width + 7) / 8;
dst = (char*) malloc(dstbyteperline*height);
}
g_object_unref(pixbuf);
// be careful to use the right scaling factor
float scx = (float)M_BMPDATA->m_width/(float)newx;
float scy = (float)M_BMPDATA->m_height/(float)newy;
// prepare accel-tables
int *tablex = (int *)calloc(width,sizeof(int));
int *tabley = (int *)calloc(height,sizeof(int));
// accel table filled with clipped values
for (int x = 0; x < width; x++)
tablex[x] = (int) (scx * (x+clipx));
for (int y = 0; y < height; y++)
tabley[y] = (int) (scy * (y+clipy));
// Main rescaling routine starts here
for (int h = 0; h < height; h++)
{
char outbyte = 0;
int old_x = -1;
guint32 old_pixval = 0;
for (int w = 0; w < width; w++)
{
guint32 pixval;
int x = tablex[w];
if (x == old_x)
pixval = old_pixval;
else
{
pixval = gdk_image_get_pixel( img, x, tabley[h] );
old_pixval = pixval;
old_x = x;
}
if ( dst )
{
if (pixval)
{
char bit=1;
char shift = bit << (w % 8);
outbyte |= shift;
}
if ((w+1)%8==0)
{
dst[h*dstbyteperline+w/8] = outbyte;
outbyte = 0;
}
}
else
{
GdkColor col;
col.pixel = pixval;
gdk_gc_set_foreground( gc, &col );
gdk_draw_point( dstpix, gc, w, h);
}
}
// do not forget the last byte
if ( dst && (width % 8 != 0) )
dst[h*dstbyteperline+width/8] = outbyte;
}
g_object_unref (img);
if (gc) g_object_unref (gc);
if ( dst )
{
bmp = wxBitmap(dst, width, height, 1);
free( dst );
}
if (GetMask())
{
dstbyteperline = (width + 7) / 8;
dst = (char*) malloc(dstbyteperline*height);
img = gdk_drawable_get_image(GetMask()->GetBitmap(), 0, 0, GetWidth(), GetHeight());
for (int h = 0; h < height; h++)
{
char outbyte = 0;
int old_x = -1;
guint32 old_pixval = 0;
for (int w = 0; w < width; w++)
{
guint32 pixval;
int x = tablex[w];
if (x == old_x)
pixval = old_pixval;
else
{
pixval = gdk_image_get_pixel( img, x, tabley[h] );
old_pixval = pixval;
old_x = x;
}
if (pixval)
{
char bit=1;
char shift = bit << (w % 8);
outbyte |= shift;
}
if ((w+1)%8 == 0)
{
dst[h*dstbyteperline+w/8] = outbyte;
outbyte = 0;
}
}
// do not forget the last byte
if (width % 8 != 0)
dst[h*dstbyteperline+width/8] = outbyte;
}
wxMask* mask = new wxMask;
mask->m_bitmap = gdk_bitmap_create_from_data( wxGetRootWindow()->window, (gchar *) dst, width, height );
bmp.SetMask(mask);
free( dst );
g_object_unref (img);
}
free( tablex );
free( tabley );
// use existing functionality to create mask from scaled pixbuf
wxBitmap maskbmp;
maskbmp.SetPixbuf(pixbuf_scaled);
bmp.SetMask(new wxMask(maskbmp, *wxBLACK));
}
return bmp;
}