Merge lp:~macslow/nux/nux.metrics into lp:nux/2.0

[Mirco Müller]

Class Metrics providing pixel->EM and EM->pixel conversion functions, thus making nux ready for resolution-independence glory... complete with unit-test. A bling-bling example program is missing currently as the typical rush-rush spree of approaching release-day and FF is dialing up other feature/bug-priorities through the roof.

[Andrea Azzarone (azzar1)]

 Copyright (C) 2011 Canonical Ltd

2012...

---

+#include "config.h"

Is this really needed?

---

57 + xres = ((((double) DisplayWidth(dpy,scr)) * 25.4) /
58 + ((double) DisplayWidthMM(dpy,scr)));
59 + yres = ((((double) DisplayHeight(dpy,scr)) * 25.4) /
60 + ((double) DisplayHeightMM(dpy,scr)));

C style cast... :(

---

+ Metrics::~Metrics ()
73 + {
74 + }

It doesn nothing, so remove it :)

---

110 +#ifndef METRICS_H
111 +#define METRICS_H

Should be NUX_MET..

---

+#include <X11/Xlib.h>

I'd prefer a fwd declaration for Display if it is possible.

---

Ah, no spaces between the function name and the bracket. And you've not pushed the unit-test :)

P.S. I'm not marking it as Need Fixing because these "issues" are not blocking.

[Andrea Azzarone (azzar1)]

Oh sorry

«And you've not pushed the unit-test»

This need to be fixed so...

review: Needs Fixing

[Mirco Müller (macslow)]

All issues, but the forward-declaration of Display, fixed. I didn't find an easy way to get around using Xlib.h there.

[lp:~macslow/nux/nux.metrics]

511. By Mirco Müller on 2012-02-14

Corrected some minor style issues, forgot to add missing unit-test earlier

[Andrea Azzarone (azzar1)]

> All issues, but the forward-declaration of Display, fixed. I didn't find an
> easy way to get around using Xlib.h there.

Looks good...

review: Approve

[Marco Trevisan (Treviño) (3v1n0)]

+ if (dpy)
54 + {
55 + // determine current system DPI, remember that: 1 inch == 2.54 cm == 25.4 mm
56 + xres = ((static_cast<double> DisplayWidth(dpy,scr) * 25.4) /
57 + (static_cast<double> DisplayWidthMM(dpy,scr)));
58 + yres = ((static_cast<double> DisplayHeight(dpy,scr) * 25.4) /
59 + (static_cast<double> DisplayHeightMM(dpy,scr)));
60 + dpi = (xres + yres) / 2.0;
61 + }

Aren't here no risks of dividing per 0? I mean, are we sure these functions won't return 0?

review: Needs Information

[Mirco Müller (macslow)]

If DisplayHeightMM() or DisplayWidthMM() are 0 you've bigger problems, than a division by zero. But for that very unlikely edge-case, I can add an additional if-statement test.

=== modified file 'Nux/Makefile.am'
--- Nux/Makefile.am	2012-02-12 22:25:19 +0000
+++ Nux/Makefile.am	2012-02-14 09:35:28 +0000
@@ -70,6 +70,7 @@
   $(srcdir)/MainLoopGLib.cpp \
   $(srcdir)/MenuPage.cpp \
   $(srcdir)/MenuBar.cpp \
+  $(srcdir)/Metrics.cpp \
   $(srcdir)/MouseAreaCtrl.cpp \
   $(srcdir)/NumericValuator.cpp \
   $(srcdir)/Nux.cpp \
@@ -153,6 +154,7 @@
   $(srcdir)/LinearLayout.h \
   $(srcdir)/MenuPage.h \
   $(srcdir)/MenuBar.h \
+  $(srcdir)/Metrics.h \
   $(srcdir)/MouseAreaCtrl.h \
   $(srcdir)/NumericValuator.h \
   $(srcdir)/Nux.h \

=== added file 'Nux/Metrics.cpp'
--- Nux/Metrics.cpp	1970-01-01 00:00:00 +0000
+++ Nux/Metrics.cpp	2012-02-14 09:35:28 +0000
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2012 Canonical Ltd
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Mirco Müller <[e-mail]
+ */
+
+#include "Nux/Metrics.h"
+
+namespace nux
+{
+  Metrics::Metrics(Display* dpy, int scr, double points)
+  {
+    double xres = 0.0;
+    double yres = 0.0;
+    double dpi  = 96.0; // default DPI if no Display provided (e.g. unit-test)
+
+    if (dpy)
+    {
+      // determine current system DPI, remember that: 1 inch == 2.54 cm == 25.4 mm
+      xres = ((static_cast<double> DisplayWidth(dpy,scr) * 25.4) /
+              (static_cast<double> DisplayWidthMM(dpy,scr)));
+      yres = ((static_cast<double> DisplayHeight(dpy,scr) * 25.4) /
+              (static_cast<double> DisplayHeightMM(dpy,scr)));
+      dpi = (xres + yres) / 2.0; 
+    }
+
+    // update stored ppe
+    pixels_per_em_ = points * dpi / 72.0;
+
+    // sanity-check
+    if (pixels_per_em_ == 0.0)
+      pixels_per_em_ = 10.0; // assume points == 10.0, dpi == 96.0
+  }
+
+  double Metrics::Pixel2EM(int value)
+  {
+    return static_cast<double> (value) / pixels_per_em_;
+  }
+
+  int Metrics::EM2Pixel(double value)
+  {
+    return static_cast<int> (value * pixels_per_em_);
+  }
+} // nux namespace
+

=== added file 'Nux/Metrics.h'
--- Nux/Metrics.h	1970-01-01 00:00:00 +0000
+++ Nux/Metrics.h	2012-02-14 09:35:28 +0000
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2012 Canonical Ltd
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authored by: Mirco Müller <[e-mail]
+ */
+
+#ifndef NUX_METRICS_H
+#define NUX_METRICS_H
+
+#include <X11/Xlib.h>
+
+namespace nux
+{
+  class Metrics
+  {
+    public:
+      Metrics(Display* dpy, int scr, double points);
+
+      double Pixel2EM(int value);
+      int EM2Pixel(double value);
+
+    private:
+      double pixels_per_em_;
+  };
+}
+
+#endif // NUX_METRICS_H

=== modified file 'tests/Makefile.am'
--- tests/Makefile.am	2012-02-12 02:24:29 +0000
+++ tests/Makefile.am	2012-02-14 09:35:28 +0000
@@ -81,6 +81,7 @@
 
 gtest_nux_SOURCES = \
   test-nux-main.cpp \
+  test-nux-metrics.cpp \
   test-nux-statictext.cpp \
   test-nux-windowthread.cpp
 

=== added file 'tests/test-nux-metrics.cpp'
--- tests/test-nux-metrics.cpp	1970-01-01 00:00:00 +0000
+++ tests/test-nux-metrics.cpp	2012-02-14 09:35:28 +0000
@@ -0,0 +1,94 @@
+#include <gtest/gtest.h>
+#include <gmock/gmock.h>
+
+#include "Nux/Nux.h"
+#include "Nux/Metrics.h"
+
+namespace {
+  TEST(TestMetrics, TestCreate)
+  {
+    // Test fallback (no display) of constructor, DPI of 96.0 will be used
+    nux::Metrics* metrics5  = new nux::Metrics(NULL, 0,  5.0);
+    nux::Metrics* metrics10 = new nux::Metrics(NULL, 0, 10.0);
+    nux::Metrics* metrics15 = new nux::Metrics(NULL, 0, 15.0);
+    nux::Metrics* metrics20 = new nux::Metrics(NULL, 0, 20.0);
+
+    // Test conversion from pixel to EM (testing fallback-case) 5-point font
+    EXPECT_EQ(metrics5->Pixel2EM(30), 4.5);
+    EXPECT_EQ(metrics5->Pixel2EM(25), 3.75);
+    EXPECT_EQ(metrics5->Pixel2EM(20), 3.0);
+    EXPECT_EQ(metrics5->Pixel2EM(15), 2.25);
+    EXPECT_EQ(metrics5->Pixel2EM(10), 1.5);
+    EXPECT_EQ(metrics5->Pixel2EM(5),  0.75);
+    EXPECT_EQ(metrics5->Pixel2EM(0),  0.0);
+
+    // Test conversion from EM to pixel (testing fallback-case) 5-point font
+    EXPECT_EQ(metrics5->EM2Pixel(4.5),  30);
+    EXPECT_EQ(metrics5->EM2Pixel(3.75), 25);
+    EXPECT_EQ(metrics5->EM2Pixel(3.0),  20);
+    EXPECT_EQ(metrics5->EM2Pixel(2.25), 15);
+    EXPECT_EQ(metrics5->EM2Pixel(1.5),  10);
+    EXPECT_EQ(metrics5->EM2Pixel(0.75),  5);
+    EXPECT_EQ(metrics5->EM2Pixel(0.0),   0);
+
+    // Test conversion from pixel to EM (testing fallback-case) 10-point font
+    EXPECT_EQ(metrics10->Pixel2EM(30), 2.25);
+    EXPECT_EQ(metrics10->Pixel2EM(25), 1.875);
+    EXPECT_EQ(metrics10->Pixel2EM(20), 1.5);
+    EXPECT_EQ(metrics10->Pixel2EM(15), 1.125);
+    EXPECT_EQ(metrics10->Pixel2EM(10), 0.75);
+    EXPECT_EQ(metrics10->Pixel2EM(5),  0.375);
+    EXPECT_EQ(metrics10->Pixel2EM(0),  0.0);
+
+    // Test conversion from EM to pixel (testing fallback-case) 10-point font
+    EXPECT_EQ(metrics10->EM2Pixel(2.25),  30);
+    EXPECT_EQ(metrics10->EM2Pixel(1.875), 25);
+    EXPECT_EQ(metrics10->EM2Pixel(1.5),   20);
+    EXPECT_EQ(metrics10->EM2Pixel(1.125), 15);
+    EXPECT_EQ(metrics10->EM2Pixel(0.75),  10);
+    EXPECT_EQ(metrics10->EM2Pixel(0.375),  5);
+    EXPECT_EQ(metrics10->EM2Pixel(0.0),    0);
+
+    // Test conversion from pixel to EM (testing fallback-case) 15-point font
+    EXPECT_EQ(metrics15->Pixel2EM(30), 1.5);
+    EXPECT_EQ(metrics15->Pixel2EM(25), 1.25);
+    EXPECT_EQ(metrics15->Pixel2EM(20), 1.0);
+    EXPECT_EQ(metrics15->Pixel2EM(15), 0.75);
+    EXPECT_EQ(metrics15->Pixel2EM(10), 0.5);
+    EXPECT_EQ(metrics15->Pixel2EM(5),  0.25);
+    EXPECT_EQ(metrics15->Pixel2EM(0),  0.0);
+
+    // Test conversion from EM to pixel (testing fallback-case) 15-point font
+    EXPECT_EQ(metrics15->EM2Pixel(1.5),  30);
+    EXPECT_EQ(metrics15->EM2Pixel(1.25), 25);
+    EXPECT_EQ(metrics15->EM2Pixel(1.0),  20);
+    EXPECT_EQ(metrics15->EM2Pixel(0.75), 15);
+    EXPECT_EQ(metrics15->EM2Pixel(0.5),  10);
+    EXPECT_EQ(metrics15->EM2Pixel(0.25),  5);
+    EXPECT_EQ(metrics15->EM2Pixel(0.0),   0);
+
+    // Test conversion from pixel to EM (testing fallback-case) 20-point font
+    EXPECT_EQ(metrics20->Pixel2EM(30), 1.125);
+    EXPECT_EQ(metrics20->Pixel2EM(25), 0.9375);
+    EXPECT_EQ(metrics20->Pixel2EM(20), 0.75);
+    EXPECT_EQ(metrics20->Pixel2EM(15), 0.5625);
+    EXPECT_EQ(metrics20->Pixel2EM(10), 0.375);
+    EXPECT_EQ(metrics20->Pixel2EM(5),  0.1875);
+    EXPECT_EQ(metrics20->Pixel2EM(0),  0.0);
+
+    // Test conversion from EM to pixel (testing fallback-case) 20-point font
+    EXPECT_EQ(metrics20->EM2Pixel(1.125),  30);
+    EXPECT_EQ(metrics20->EM2Pixel(0.9375), 25);
+    EXPECT_EQ(metrics20->EM2Pixel(0.75),   20);
+    EXPECT_EQ(metrics20->EM2Pixel(0.5625), 15);
+    EXPECT_EQ(metrics20->EM2Pixel(0.375),  10);
+    EXPECT_EQ(metrics20->EM2Pixel(0.1875),  5);
+    EXPECT_EQ(metrics20->EM2Pixel(0.0),     0);
+
+    delete metrics5;
+    delete metrics10;
+    delete metrics15;
+    delete metrics20;
+  }
+} // unnamed namespace
+