Fix minor errors with text view margins for console/info editor

- Margins used duplicate define between files.
- Cursor selection ignored margins.
- Cursor wasn't scaling with DPI.

Add a 'draw_rect' member which is the region rect with margins applied
to make these checks clearer.

This resolves issue pointed out in D6300,
which complicated further refactoring.

3 files changed, 40 insertions, 18 deletions

diff --git a/source/blender/editors/space_info/info_draw.c b/source/blender/editors/space_info/info_draw.c
index 734515e1f79..a22983c15a8 100644
--- a/source/blender/editors/space_info/info_draw.c
+++ b/source/blender/editors/space_info/info_draw.c
@@ -228,6 +228,16 @@ static int report_textview_line_color(struct TextViewContext *tvc,
 
 #undef USE_INFO_NEWLINE
 
+static void info_textview_draw_rect_calc(ARegion *ar, rcti *draw_rect)
+{
+  const int margin = 4 * UI_DPI_FAC;
+  draw_rect->xmin = margin;
+  draw_rect->xmax = ar->winx - (V2D_SCROLL_WIDTH + margin);
+  draw_rect->ymin = margin;
+  /* No margin at the top (allow text to scroll off the window). */
+  draw_rect->ymax = ar->winy;
+}
+
 static int info_textview_main__internal(struct SpaceInfo *sinfo,
                                         ARegion *ar,
                                         ReportList *reports,
@@ -258,7 +268,8 @@ static int info_textview_main__internal(struct SpaceInfo *sinfo,
   tvc.lheight = 14 * UI_DPI_FAC;  // sc->lheight;
   tvc.ymin = v2d->cur.ymin;
   tvc.ymax = v2d->cur.ymax;
-  tvc.winx = ar->winx - V2D_SCROLL_WIDTH;
+
+  info_textview_draw_rect_calc(ar, &tvc.draw_rect);
 
   ret = textview_draw(&tvc, draw, mval, mouse_pick, pos_pick);
 
diff --git a/source/blender/editors/space_info/textview.c b/source/blender/editors/space_info/textview.c
index 97d5faa9c13..0ebd8bdc065 100644
--- a/source/blender/editors/space_info/textview.c
+++ b/source/blender/editors/space_info/textview.c
@@ -51,7 +51,7 @@ typedef struct ConsoleDrawContext {
   int lofs;
   /** number of characters that fit into the width of the console (fixed width) */
   int console_width;
-  int winx;
+  const rcti *draw_rect;
   int ymin, ymax;
   int *xy;   // [2]
   int *sel;  // [2]
@@ -201,7 +201,8 @@ static int console_draw_string(ConsoleDrawContext *cdc,
       immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);
 
       immUniformColor3ubv(bg);
-      immRecti(pos, 0, cdc->xy[1], cdc->winx, (cdc->xy[1] + (cdc->lheight * tot_lines)));
+      immRecti(
+          pos, 0, cdc->xy[1], cdc->draw_rect->xmax, (cdc->xy[1] + (cdc->lheight * tot_lines)));
 
       immUnbindProgram();
     }
@@ -252,7 +253,7 @@ static int console_draw_string(ConsoleDrawContext *cdc,
       immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);
 
       immUniformColor3ubv(bg);
-      immRecti(pos, 0, cdc->xy[1], cdc->winx, cdc->xy[1] + cdc->lheight);
+      immRecti(pos, 0, cdc->xy[1], cdc->draw_rect->xmax, cdc->xy[1] + cdc->lheight);
 
       immUnbindProgram();
     }
@@ -284,15 +285,13 @@ static int console_draw_string(ConsoleDrawContext *cdc,
   return 1;
 }
 
-#define CONSOLE_DRAW_MARGIN 4
-
 int textview_draw(
-    TextViewContext *tvc, const int draw, int mval[2], void **mouse_pick, int *pos_pick)
+    TextViewContext *tvc, const int draw, const int mval_init[2], void **mouse_pick, int *pos_pick)
 {
   ConsoleDrawContext cdc = {0};
 
-  int x_orig = CONSOLE_DRAW_MARGIN, y_orig = CONSOLE_DRAW_MARGIN + tvc->lheight / 6;
-  int xy[2], y_prev;
+  int x_orig = tvc->draw_rect.xmin, y_orig = tvc->draw_rect.ymin + tvc->lheight / 6;
+  int xy[2];
   int sel[2] = {-1, -1}; /* defaults disabled */
   unsigned char fg[3], bg[3];
   const int font_id = blf_mono_font;
@@ -302,9 +301,16 @@ int textview_draw(
   xy[0] = x_orig;
   xy[1] = y_orig;
 
-  if (mval[1] != INT_MAX) {
-    mval[1] += (tvc->ymin + CONSOLE_DRAW_MARGIN);
-  }
+  /* Offset and clamp the results,
+   * clamping so moving the cursor out of the bounds doesn't weap onto the other lines. */
+  const int mval[2] = {
+      (mval_init[0] == INT_MAX) ?
+          INT_MAX :
+          CLAMPIS(mval_init[0], tvc->draw_rect.xmin, tvc->draw_rect.xmax) - tvc->draw_rect.xmin,
+      (mval_init[1] == INT_MAX) ?
+          INT_MAX :
+          CLAMPIS(mval_init[1], tvc->draw_rect.ymin, tvc->draw_rect.ymax) + tvc->ymin,
+  };
 
   if (pos_pick) {
     *pos_pick = 0;
@@ -317,12 +323,12 @@ int textview_draw(
   cdc.lheight = tvc->lheight;
   cdc.lofs = -BLF_descender(font_id);
   /* note, scroll bar must be already subtracted () */
-  cdc.console_width = (tvc->winx - (CONSOLE_DRAW_MARGIN * 2)) / cdc.cwidth;
+  cdc.console_width = (tvc->draw_rect.xmax - tvc->draw_rect.xmin) / cdc.cwidth;
   /* avoid divide by zero on small windows */
   if (cdc.console_width < 1) {
     cdc.console_width = 1;
   }
-  cdc.winx = tvc->winx - CONSOLE_DRAW_MARGIN;
+  cdc.draw_rect = &tvc->draw_rect;
   cdc.ymin = tvc->ymin;
   cdc.ymax = tvc->ymax;
   cdc.xy = xy;
@@ -353,7 +359,7 @@ int textview_draw(
       int ext_len;
       int color_flag = 0;
 
-      y_prev = xy[1];
+      const int y_prev = xy[1];
 
       if (draw) {
         color_flag = tvc->line_color(tvc, fg, bg);
diff --git a/source/blender/editors/space_info/textview.h b/source/blender/editors/space_info/textview.h
index aa0e924b461..ca5744dbe90 100644
--- a/source/blender/editors/space_info/textview.h
+++ b/source/blender/editors/space_info/textview.h
@@ -29,7 +29,9 @@ typedef struct TextViewContext {
   int cwidth;        /* shouldnt be needed! */
   int console_width; /* shouldnt be needed! */
 
-  int winx;
+  /** Area to draw: (0, 0, winx, winy) with a margin applied and scroll-bar subtracted. */
+  rcti draw_rect;
+
   int ymin, ymax;
 
   /* callbacks */
@@ -52,8 +54,11 @@ typedef struct TextViewContext {
 
 } TextViewContext;
 
-int textview_draw(
-    struct TextViewContext *tvc, const int draw, int mval[2], void **mouse_pick, int *pos_pick);
+int textview_draw(struct TextViewContext *tvc,
+                  const int draw,
+                  const int mval_init[2],
+                  void **mouse_pick,
+                  int *pos_pick);
 
 #define TVC_LINE_FG (1 << 0)
 #define TVC_LINE_BG (1 << 1)