I am basing my code on the p_w_picpaths1 example and I have changed
the p_w_picpath 'partner' shape from an ellipse to a rectangle.
The partner rectangle comes out at X,Y and scales and rotates,
but the top left-hand corner of the p_w_picpath is always stuck at
(x,y)=3D(0,0). Only the part of the p_w_picpath that overlaps the=20
rectangle is visible, but that part scales and rotates properly.=20
When there is no overlap, there is no p_w_picpath.
I do not understand much of the the p_w_picpath2 example, so I am
lost as to what might be.the cause. Code is attached.
Would be most grateful for help and/or example code.
void p_w_picpath ( HAGG * h , int x , int y , TCHAR * imgfilename )
{
if ( !loadp_w_picpath ( h , imgfilename ) ) // sets p_w_picpath details in h
{
return ;
}
agg::rendering_buffer rbuf(h->pixels ,
h->frame_width ,=20
h->frame_height ,=20
-(h->frame_width * h->bytesperpixel) ) ;=20
typedef agg::renderer_base
typedef agg::renderer_base
renderer_base_pre;
typedef agg::renderer_scanline_aa_solid
renderer_solid;
pixfmt pixf(rbuf);
pixfmt_pre pixf_pre(rbuf);
renderer_base rb(pixf);
renderer_base_pre rb_pre(pixf_pre);
renderer_solid rs(rb);
rb.clear(agg::rgba(1.0, 1.0, 1.0));
agg::rasterizer_scanline_aa<> pf;
agg::scanline_u8 sl;
IMGINFO * i =3D &h->imgs [ 0 ] ;
double imgwd =3D i->width ; // p_w_picpath width
double imght =3D i->height ; // p_w_picpath height
agg::trans_affine src_mtx;
src_mtx *=3D agg::trans_affine_translation(-x,-y);
src_mtx *=3D agg::trans_affine_rotation(-h->t.angle); // in radians
src_mtx *=3D agg::trans_affine_scaling(h->t.scalex , h->t.scaley);
src_mtx *=3D agg::trans_affine_translation(x,y);
agg::trans_affine img_mtx;
img_mtx *=3D agg::trans_affine_translation(-x,-y);
img_mtx *=3D agg::trans_affine_rotation(-h->t.angle);
img_mtx *=3D agg::trans_affine_scaling(h->t.scalex , h->t.scaley);
img_mtx *=3D agg::trans_affine_translation(x,y);
img_mtx.invert();
typedef agg::span_allocator
span_alloc_type sa;
typedef agg::span_interpolator_linear<> interpolator_type;
interpolator_type interpolator(img_mtx);
// "hardcoded" bilinear filter
typedef agg::span_p_w_picpath_filter_rgb_bilinear component_order,=20 interpolator_type> = span_gen_type; typedef agg::renderer_scanline_aa renderer_type; agg::rendering_buffer rbuf_img(i->pixels , (int)imgwd ,=20 (int)imght ,=20 -i->stride ) ;=20 span_gen_type sg(sa,=20 rbuf_img, // rendering buf with p_w_picpath pixels agg::rgba_pre(0, 0.4, 0, 0.5), interpolator); renderer_type ri(rb_pre, sg); agg::path_storage path; // partner rectangle path.move_to( x,y); path.line_to( x+imgwd, y ); path.line_to( x+imgwd, y+imght); path.line_to( x, y+imght); path.close_polygon(); agg::conv_transform =20 pf.add_path(tr); agg::render_scanlines(pf, sl, ri); } static void drawp_w_picpath ( ) { RECT rt ; GetClientRect(hwndmain, &rt); int width =3D rt.right - rt.left; int height =3D rt.bottom - rt.top; HAGG * h =3D gethandle ( mybuf , width , height , 4 ) ; settrans_scale ( h , scale ) ; settrans_rotate ( h , degrees ) ; // p_w_picpath ( h , 20,50 , "bmpeivor.bmp" ) ; // does not work p_w_picpath ( h , 0,0 , "bmpeivor.bmp" ) ; // works display ( h , hwndmain ) ; // on screen } 作者的回答： Transforming p_w_picpaths is tricky, especially proper calculation of the affine matrix. But first, if you don't need to transform it you can directly copy or blend the p_w_picpath, it will work much faster. See renderer_base<>::copy_from(), blend_from(). For the transformer there's a simple way of calculating the matrix as a parallelogram, see p_w_picpath_perspective.cpp // Note that we consruct an affine matrix that transforms // a parallelogram to a rectangle, i.e., it's inverted. // It's actually the same as: // tr(0, 0, img_width, img_height, para); tr.invert(); agg::trans_affine tr(para, 0, 0, img_width, img_height); Where "para" is double[6] that defines 3 point of the parallelogram. 困惑： I have replaced agg::path_storage path; // partner rectangle path.move_to( x,y); path.line_to( x+imgwd, y ); pathmline_to( x+imgwd, y+imght); path.line_to( x, y+imght); path.close_polygon(); agg::conv_transform pf.add_path(tr); agg::render_scanlines(pf, sl, ri); at the and of my p_w_picpath proc (code of the whole proc is at the end of my original post (and at the end of this email)) by double para [ 6 ] = { 0,100 , 0,0 , 100.0 } ; // 3 points (0,100) (0,0) and (100,0) agg::trans_affine tr(para, 0, 0, imgwd, imght); pf.add_path(tr); agg::render_scanlines(pf, sl, ri); Q1. is this the right way? Q2. what should the para points be expressed as functions of p_w_picpath top-left hand corner, p_w_picpath width and p_w_picpath height, i.e. x,y, imgwd, imght? My test cases includes p_w_picpath (x,y)=(0,0), so I defined para points (0,100), (0,0) and (100,0) just to see what would happen. but got compilation errors: ..\agg23\include\agg_rasterizer_scanline_aa.h(465) : error C2039: 'rewind' : is not a member of 'trans_affine' ..\agg23\include\agg_trans_affine.h(88) : see declaration of 'trans_affine' and one more very similar: 'vertex' : is not a member of 'trans_affine' 作者的回答： > double para [ 6 ] = { 0,100 , 0,0 , 100,0 } ; // 3 points (0,100) (0,0) > and (100,0) > agg::trans_affine mtx(para, 0, 0, imgwd, imght); > agg::path_storage path; // partner rectangle > path.move_to( x,y); > path.line_to( x+imgwd, y ); > path.line_to( x+imgwd, y+imght); > path.line_to( x, y+imght); > path.close_polygon(); > agg::conv_transform > mtx); > > pf.add_path(trans); // Note you add "trans" > > Then, if you want your p_w_picpath to fit exactly your parallelogram path (you > also may want to do differently!), you need to create a copy of the matrix > and invert it: > > agg::trans_affine img_mtx(mtx); > img_mtx.invert(); I'm sorry, Ken, this is not correct; I have confused myself, so, please discard the code above. :) So, suppose you have an p_w_picpath of imgwd, imght and a destination parallelogram. To define the parallelogram you need 3 points, x1,y1 - bottom left, x2,y2 - bottom right, x3,y3 - top right. The parallelogram can also define a 2D affine matrix: rotation, scaling, translation and skewing. You can rasterize your destination parallelogram directly: agg::rasterizer_scanline_aa<> ras; ras.move_to_d(x1,y1); ras.line_to_d(x2,y2); ras.line_to_d(x3,y3); ras.line_to_d(x1 + x3 - x2, y1 + y3 - y2); So that, you can draw a solid parallelogram (well, you can also use the path_storage if you want). To map an p_w_picpath to it you need to create the matrix: double para[6] = {x1,y1,x2,y2,x3,y3}; agg::trans_affine img_mtx(0, 0, imgwd, imght, para); img_mtx.invert(); Or, which is the same: double para[6] = {x1,y1,x2,y2,x3,y3}; agg::trans_affine img_mtx(para, 0, 0, imgwd, imght); The first one construicts a matrix to transform a rectangle to a a parellelogram, the second one - parallelogram to rectangle. The p_w_picpath transformer requires namely inverse matrix, so that, you transform your parallelogram (destination) to rectangle (p_w_picpath). Technically that's it. But you may want to apply additional transformations. To do that you will need two matrices: agg::trans_affine master_mtx; master_mtx *= agg::trans_affine_translation(. . .); master_mtx *= agg::trans_affine_rotation(. . .); . . . agg::rasterizer_scanline_aa<> ras; agg::path_storage path; // partner rectangle path.move_to(x1,y1); path.line_to(x2,y2); path.line_to(x3,y3); path.line_to(x1 + x3 - x2, y1 + y3 - y2); path.close_polygon(); agg::conv_transform master_mtx); Then you prepare the p_w_picpath matrix: double para[6] = {x1,y1,x2,y2,x3,y3}; agg::trans_affine img_mtx(0, 0, imgwd, imght, para); img_mtx *= master_mtx; //!!!!!!!!!!!!! Integrate the master transforms img_mtx.invert(); ras.add_path(trans); . . .Render Now, whatever transformations you use in the master_mtxà they will be synchronized with the p_w_picpath. Sorry for the delay, I was kinda busy last time. and besides, I'm suffering from constant problems with the Internet (Verizon in NYC sucks, I'm switching to cable). Well, I understand everyone is busy, but could someone else answer the questions too? First, you need to understand that a path is the primary thing in AGG. Without path you can't draw anything. So that, to rotate an p_w_picpath you need to create a respective path as if you wanted to fill this area with a solid color. And then, you just substitute an p_w_picpath renderer for your solid fill. Obviously, to transform the whole p_w_picpath you need to create a parallelogram path (a rectangle in particular). You can do that calculating the points manually: ras.move_to_d(x1, y1); ras.line_to_d(x2, y2); . . . You you can use transformations. Next, trans_affine doesn't have any "VertexSource" interface, it can't generate vertices. It can only transform them: affine.transform(&x, &y); To add affine transformer into your pipeline you also need conv_transform: double para [ 6 ] = { 0,100 , 0,0 , 100,0 } ; // 3 points (0,100) (0,0) and (100,0) agg::trans_affine mtx(para, 0, 0, imgwd, imght); agg::path_storage path; // partner rectangle path.move_to( x,y); path.line_to( x+imgwd, y ); path.line_to( x+imgwd, y+imght); path.line_to( x, y+imght); path.close_polygon(); agg::conv_transform pf.add_path(trans); // Note you add "trans" Then, if you want your p_w_picpath to fit exactly your parallelogram path (you also may want to do differently!), you need to create a copy of the matrix and invert it: agg::trans_affine img_mtx(mtx); img_mtx.invert(); Well, I realize that it all is pretty confusing. But this kind of a design is most flexible. 摘自：http://sourceforge.net/p/vector-agg/mailman/vector-agg-general/?viewmonth=200511&page=0 另外有需要云服务器可以了解下创新互联scvps.cn，海内外云服务器15元起步，三天无理由+7*72小时售后在线，公司持有idc许可证，提供“云服务器、裸金属服务器、高防服务器、香港服务器、美国服务器、虚拟主机、免备案服务器”等云主机租用服务以及企业上云的综合解决方案，具有“安全稳定、简单易用、服务可用性高、性价比高”等特点与优势，专为企业上云打造定制，能够满足用户丰富、多元化的应用场景需求。
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