[rrd-developers] Re: Strange Y labels in 1.2.9 with --alt-autoscale
Tobias Oetiker
oetiker at ee.ethz.ch
Thu Jun 16 22:21:43 MEST 2005
Monday Kai Risku wrote:
> Hi!
> The patch made things a little better, but it is still not perfect. Now
> the labels do get a decimal, but there is still some unwanted rounding
> going on.
>
> I inserted the following debug-statement into draw_horizontal_grid:
>
> fprintf(stderr, "graph_label = '%s' for %7.4f\n",
> graph_label, scaledstep*im->viewfactor*i);
>
> And this is the result:
>
> graph_label = '68.0 G' for 67.9865
> graph_label = '68.2 G' for 68.1728
> graph_label = '68.4 G' for 68.3591
> graph_label = '68.5 G' for 68.5453
> graph_label = '68.7 G' for 68.7316
:-) so how about this:
Index: rrd_graph.c
===================================================================
--- rrd_graph.c (revision 639)
+++ rrd_graph.c (working copy)
@@ -1547,7 +1547,7 @@
if(decimals <= 0) /* everything is small. make place for zero */
decimals = 1;
- im->ygrid_scale.gridstep = pow((double)10, floor(log10(range)));
+ im->ygrid_scale.gridstep = pow((double)10, floor(log10(range*im->viewfactor/im->magfact)))/im->viewfactor*im->magfact;
if(im->ygrid_scale.gridstep == 0) /* range is one -> 0.1 is reasonable scale */
im->ygrid_scale.gridstep = 0.1;
cheers
tobi
>
> Some further debugging reveals that this only happens when using base
> 1024, and then I just realized what is happening! The gridlines are
> actually placed on nice even numbers according to base 1000, but then
> the values recalculated to base 1024 become what can be seen in my
> printf-debugging above.
>
> Perhaps this insight gives Tobi enough ideas to come up with a
> definitive fix!
>
> Regards,
> Kai
>
> --
> Kai.Risku at arrak.fi GSM +358-40-767 8282
> Oy Arrak Software Ab http://www.arrak.fi
>
>
> > -----Original Message-----
> > From: Tobias Oetiker [mailto:oetiker at ee.ethz.ch]
> > Sent: Sunday, 12 June, 2005 23:37
> > To: Kai Risku
> > Cc: rrd-developers at list.ee.ethz.ch
> > Subject: Re: [rrd-developers] Re: Strange Y labels in 1.2.9 with
> --alt-
> > autoscale
> >
> > Hi Kai,
> >
> > you might want to try this:
> >
> > Index: rrd_graph.c
> > ===================================================================
> > --- rrd_graph.c (revision 620)
> > +++ rrd_graph.c (working copy)
> > @@ -394,7 +394,7 @@
> > delt = im->maxval - im->minval;
> > adj = delt * 0.1;
> > fact = 2.0 * pow(10.0,
> > - floor(log10(max(fabs(im->minval), fabs(im-
> > >maxval)))) - 2);
> > + floor(log10(max(fabs(im->minval), fabs(im-
> > >maxval))/im->magfact)) - 2);
> > if (delt < fact) {
> > adj = (fact - delt) * 0.55;
> > #ifdef DEBUG
> > @@ -432,10 +432,6 @@
> > -sensiblevalues[i] >=scaled_max)
> > im->maxval = -sensiblevalues[i]*(im->magfact);
> > }
> > - /* no sensiblevalues found. we switch to ALTYGRID mode */
> > - if (sensiblevalues[i] == 0){
> > - im->extra_flags |= ALTYGRID;
> > - }
> > }
> > } else {
> > /* adjust min and max to the grid definition if there is one */
> > @@ -1549,21 +1545,12 @@
> > if(isnan(im->ygridstep)){
> > if(im->extra_flags & ALTYGRID) {
> > /* find the value with max number of digits. Get number of
> > digits */
> > - decimals = ceil(log10(max(fabs(im->maxval), fabs(im-
> > >minval))));
> > + decimals = ceil(log10(max(fabs(im->maxval), fabs(im-
> > >minval))*im->viewfactor/im->magfact));
> > if(decimals <= 0) /* everything is small. make place for
> > zero */
> > decimals = 1;
> >
> > - fractionals = floor(log10(range));
> > - if(fractionals < 0) { /* small amplitude. */
> > - int len = decimals - fractionals + 1;
> > - if (im->unitslength < len) im->unitslength = len;
> > - sprintf(im->ygrid_scale.labfmt, "%%%d.%df", len, -
> > fractionals + 1);
> > - } else {
> > - int len = decimals + 1;
> > - if (im->unitslength < len) im->unitslength = len;
> > - sprintf(im->ygrid_scale.labfmt, "%%%d.1f", len);
> > - }
> > - im->ygrid_scale.gridstep = pow((double)10,
> > (double)fractionals);
> > + im->ygrid_scale.gridstep = pow((double)10,
> > floor(log10(range)));
> > +
> > if(im->ygrid_scale.gridstep == 0) /* range is one -> 0.1 is
> > reasonable scale */
> > im->ygrid_scale.gridstep = 0.1;
> > /* should have at least 5 lines but no more then 15 */
> > @@ -1580,6 +1567,16 @@
> > im->ygrid_scale.gridstep /= 5;
> > im->ygrid_scale.labfact = 5;
> > }
> > + fractionals = floor(log10(im-
> >
> >ygrid_scale.gridstep*(double)im->ygrid_scale.labfact*im->viewfactor/im-
> > >magfact));
> > + if(fractionals < 0) { /* small amplitude. */
> > + int len = decimals - fractionals + 1;
> > + if (im->unitslength < len+2) im->unitslength =
> > len+2;
> > + sprintf(im->ygrid_scale.labfmt, "%%%d.%df%s", len, -
> > fractionals,(im->symbol != ' ' ? " %c" : ""));
> > + } else {
> > + int len = decimals + 1;
> > + if (im->unitslength < len+2) im->unitslength =
> > len+2;
> > + sprintf(im->ygrid_scale.labfmt, "%%%d.1f%s", len, (
> > im->symbol != ' ' ? " %c" : "" ));
> > + }
> > }
> > else {
> > for(i=0;ylab[i].grid > 0;i++){
> > @@ -1624,23 +1621,27 @@
> > if ( Y0 >= im->yorigin-im->ysize
> > && Y0 <= im->yorigin){
> > if(i % im->ygrid_scale.labfact == 0){
> > - if (i==0 || im->symbol == ' ') {
> > - if(MaxY < 10) {
> > - if(im->extra_flags & ALTYGRID) {
> > - sprintf(graph_label,im-
> > >ygrid_scale.labfmt,scaledstep*im->viewfactor*i);
> > - }
> > - else {
> > -
> > sprintf(graph_label,"%4.1f",scaledstep*im->viewfactor*i);
> > - }
> > - } else {
> > -
> > sprintf(graph_label,"%4.0f",scaledstep*im->viewfactor*i);
> > - }
> > + if (im->symbol == ' ') {
> > + if(im->extra_flags & ALTYGRID) {
> > + sprintf(graph_label,im-
> > >ygrid_scale.labfmt,scaledstep*im->viewfactor*i);
> > + } else {
> > + if(MaxY < 10) {
> > +
> > sprintf(graph_label,"%4.1f",scaledstep*im->viewfactor*i);
> > + } else {
> > +
> > sprintf(graph_label,"%4.0f",scaledstep*im->viewfactor*i);
> > + }
> > + }
> > }else {
> > - if(MaxY < 10){
> > - sprintf(graph_label,"%4.1f
> > %c",scaledstep*im->viewfactor*i, im->symbol);
> > - } else {
> > - sprintf(graph_label,"%4.0f
> > %c",scaledstep*im->viewfactor*i, im->symbol);
> > - }
> > + char sisym = ( i == 0 ? ' ' : im->symbol);
> > + if(im->extra_flags & ALTYGRID) {
> > + sprintf(graph_label,im-
> > >ygrid_scale.labfmt,scaledstep*im->viewfactor*i,sisym);
> > + } else {
> > + if(MaxY < 10){
> > + sprintf(graph_label,"%4.1f
> > %c",scaledstep*im->viewfactor*i, sisym);
> > + } else {
> > + sprintf(graph_label,"%4.0f
> > %c",scaledstep*im->viewfactor*i, sisym);
> > + }
> > + }
> > }
> >
> > gfx_new_text ( im->canvas,
> >
> > --
> > ______ __ _
> > /_ __/_ / / (_) Oetiker @ ISG.EE, ETL F24.2, ETH, CH-8092 Zurich
> > / // _ \/ _ \/ / System Manager, Time Lord, Coder, Designer, Coach
> > /_/ \.__/_.__/_/ http://people.ee.ethz.ch/oetiker +41(0)44-632-5286
>
--
______ __ _
/_ __/_ / / (_) Oetiker @ ISG.EE, ETL F24.2, ETH, CH-8092 Zurich
/ // _ \/ _ \/ / System Manager, Time Lord, Coder, Designer, Coach
/_/ \.__/_.__/_/ http://people.ee.ethz.ch/oetiker +41(0)44-632-5286
--
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