Michael Stapelberg
7 years ago
6 changed files with 144 additions and 14 deletions
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/*
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* vim:ts=4:sw=4:expandtab |
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* |
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* i3 - an improved dynamic tiling window manager |
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* © 2009 Michael Stapelberg and contributors (see also: LICENSE) |
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* |
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*/ |
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#include "dpi.h" |
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#include <math.h> |
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#include <stdlib.h> |
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#include <stdio.h> |
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#include <xcb/xcb_xrm.h> |
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#include "xcb.h" |
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#include "i3lock.h" |
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extern bool debug_mode; |
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static long dpi; |
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extern xcb_screen_t *screen; |
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static long init_dpi_fallback(void) { |
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return (double)screen->height_in_pixels * 25.4 / (double)screen->height_in_millimeters; |
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} |
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/*
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* Initialize the DPI setting. |
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* This will use the 'Xft.dpi' X resource if available and fall back to |
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* guessing the correct value otherwise. |
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*/ |
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void init_dpi(void) { |
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xcb_xrm_database_t *database = NULL; |
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char *resource = NULL; |
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if (conn == NULL) { |
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goto init_dpi_end; |
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} |
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database = xcb_xrm_database_from_default(conn); |
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if (database == NULL) { |
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DEBUG("Failed to open the resource database.\n"); |
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goto init_dpi_end; |
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} |
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xcb_xrm_resource_get_string(database, "Xft.dpi", NULL, &resource); |
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if (resource == NULL) { |
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DEBUG("Resource Xft.dpi not specified, skipping.\n"); |
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goto init_dpi_end; |
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} |
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char *endptr; |
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double in_dpi = strtod(resource, &endptr); |
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if (in_dpi == HUGE_VAL || dpi < 0 || *endptr != '\0' || endptr == resource) { |
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DEBUG("Xft.dpi = %s is an invalid number and couldn't be parsed.\n", resource); |
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dpi = 0; |
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goto init_dpi_end; |
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} |
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dpi = (long)round(in_dpi); |
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DEBUG("Found Xft.dpi = %ld.\n", dpi); |
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init_dpi_end: |
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if (resource != NULL) { |
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free(resource); |
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} |
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if (database != NULL) { |
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xcb_xrm_database_free(database); |
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} |
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if (dpi == 0) { |
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DEBUG("Using fallback for calculating DPI.\n"); |
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dpi = init_dpi_fallback(); |
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DEBUG("Using dpi = %ld\n", dpi); |
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} |
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} |
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/*
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* This function returns the value of the DPI setting. |
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* |
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*/ |
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long get_dpi_value(void) { |
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return dpi; |
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} |
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/*
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* Convert a logical amount of pixels (e.g. 2 pixels on a “standard” 96 DPI |
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* screen) to a corresponding amount of physical pixels on a standard or retina |
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* screen, e.g. 5 pixels on a 227 DPI MacBook Pro 13" Retina screen. |
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* |
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*/ |
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int logical_px(const int logical) { |
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if (screen == NULL) { |
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/* Dpi info may not be available when parsing a config without an X
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* server, such as for config file validation. */ |
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return logical; |
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} |
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/* There are many misconfigurations out there, i.e. systems with screens
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* whose dpi is in fact higher than 96 dpi, but not significantly higher, |
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* so software was never adapted. We could tell people to reconfigure their |
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* systems to 96 dpi in order to get the behavior they expect/are used to, |
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* but since we can easily detect this case in code, let’s do it for them. |
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*/ |
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if ((dpi / 96.0) < 1.25) |
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return logical; |
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return ceil((dpi / 96.0) * logical); |
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} |
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@ -0,0 +1,22 @@ |
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#pragma once |
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/**
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* Initialize the DPI setting. |
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* This will use the 'Xft.dpi' X resource if available and fall back to |
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* guessing the correct value otherwise. |
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*/ |
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void init_dpi(void); |
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/**
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* This function returns the value of the DPI setting. |
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* |
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*/ |
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long get_dpi_value(void); |
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/**
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* Convert a logical amount of pixels (e.g. 2 pixels on a “standard” 96 DPI |
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* screen) to a corresponding amount of physical pixels on a standard or retina |
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* screen, e.g. 5 pixels on a 227 DPI MacBook Pro 13" Retina screen. |
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* |
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*/ |
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int logical_px(const int logical); |
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